jQuery and legacy patterns

15 Dec

Audio Block

Double-click here to upload or link to a .mp3. Learn more

TL;DR.

This lecture explores the significance of jQuery in web development, detailing its functionalities, common tasks, and best practices for developers. It also discusses when to use or avoid jQuery in favour of modern alternatives.

Main Points.

Overview of jQuery:
- jQuery simplifies JavaScript for web development.
- It provides a unified API for common tasks.
- jQuery accelerates development when native APIs are lacking.
- Many older sites still depend on jQuery for functionality.
Common tasks with jQuery:
- Selecting elements and handling events efficiently.
- Updating the DOM without causing performance issues.
- Implementing animations and effects judiciously.
When not to use jQuery:
- When modern native APIs cover the need cleanly.
- When it adds unnecessary weight and complexity.
- When performance is critical on mobile devices.
- When the team isn’t aligned on its use.

Conclusion.

jQuery remains a relevant tool in web development, particularly for legacy support and rapid prototyping. Developers should understand its strengths and limitations, considering modern alternatives for new projects while leveraging jQuery for maintaining existing codebases. Staying informed about evolving web standards will empower developers to make informed decisions about their technology stack.

Key takeaways.

jQuery simplifies JavaScript tasks, enhancing productivity.
It provides a unified API for consistent cross-browser functionality.
Many legacy projects still rely on jQuery for maintenance.
Common tasks include DOM manipulation, event handling, and animations.
Consider modern native APIs for cleaner solutions when possible.
jQuery can add unnecessary complexity in modern frameworks.
Performance is critical; test jQuery effects on mobile devices.
Understanding jQuery is essential for maintaining legacy code.
Stay informed about evolving web standards and best practices.
jQuery remains valuable for quick prototyping and legacy support.

Play section audio

What jQuery is.

jQuery’s role in web development.

jQuery is a lightweight JavaScript library built to make common front-end tasks faster to write and easier to maintain. Instead of repeatedly working through the lower-level details of browser scripting, it provides a concise API for selecting elements, responding to user actions, animating UI, and making network requests. The overall intent is practical: reduce the amount of code required to ship a usable interface while keeping the codebase understandable for teams with mixed experience.

Its “write less, do more” idea works because it wraps frequent workflows into predictable methods. A single call can find elements, update attributes, insert content, bind events, and orchestrate small UI changes. This was especially valuable when front-end work involved a lot of repetitive boilerplate and when minor differences between browsers created fragile code. Even now, this approach can speed up work on small feature additions where introducing a larger framework would be unnecessary overhead.

In day-to-day terms, a team maintaining a marketing site, a services website, or a small e-commerce storefront often needs quick enhancements: show and hide sections, validate a form, update pricing displays, or load content without refreshing the page. Those are the types of problems the library was designed to solve. That also explains why it remains common in older themes and templates that still run real businesses.

How it simplifies DOM work.

The main workflow jQuery streamlines is interacting with the Document Object Model (DOM). In a browser, the DOM is the live object representation of a webpage, where headings, buttons, images, and form inputs become nodes that scripts can query and change. Without a helper library, developers typically write longer code to locate elements, loop through collections, handle cross-browser differences, and ensure operations occur at the right time in the page lifecycle.

jQuery compresses these patterns into a small set of consistent behaviours. Element selection uses a familiar CSS-selector style, and operations can be applied to one element or many with the same syntax. That matters in real production sites because UI changes rarely target a single node. Consider a product list where each item needs a “quick view” toggle, or a grid of cards where hover behaviour should be applied uniformly. A team can target a class once, apply behaviour once, and rely on predictable results across the whole set.

It also encourages a readable style through method chaining. Instead of storing intermediate variables and repeatedly re-selecting elements, multiple operations can run in sequence on the same selection. This can keep code compact, but the real advantage is maintainability: changes become easier when the selection and its transformations are expressed as one coherent chain rather than scattered statements. Teams doing rapid iterations, such as growth experiments or content-driven landing page updates, often value that clarity.

Event handling without friction.

Interactive sites depend on a reliable model for user interaction: clicks, keyboard input, scrolling, focus states, and dynamic elements that appear later. jQuery standardises event handling so developers can attach behaviour with less boilerplate and with fewer surprises across browsers. This matters when a site must support a wide range of devices, including older mobile browsers that may behave inconsistently with native event APIs.

A common real-world scenario is delegated events. When a site renders new elements dynamically, such as adding cart items, loading additional FAQs, or expanding a menu from a CMS-driven structure, binding events directly to elements can fail if those elements did not exist at initial page load. jQuery popularised a pattern where events are attached to a stable parent and “delegated” to matching children, allowing new content to inherit behaviour automatically. This is particularly useful in content management environments where templates generate repeating components and where the exact number of elements can change without a developer touching the code.

There are also practical safeguards: consistent normalisation of event objects, easier prevention of default behaviours (such as stopping a link from navigating during a UI-only action), and simplified patterns for working with form submissions. In small teams where developers also handle operations and marketing tasks, being able to implement these behaviours quickly can prevent workflow bottlenecks.

Asynchronous requests and partial page updates.

Before modern browser tooling matured, AJAX was one of the biggest reasons developers adopted jQuery. It offered an approachable way to fetch data or HTML fragments without refreshing the page. While the web platform now includes native options for this, the library’s API still provides a familiar structure for older codebases and for projects where consistency matters more than using the newest interface.

AJAX matters for business outcomes because it can reduce friction. A services site can submit a contact form and show confirmation in place, rather than redirecting the user. An e-commerce site can update shipping costs, availability, or totals without forcing a full refresh. A SaaS marketing page can load testimonials or pricing details on demand. Each of these patterns reduces “page jump” moments that interrupt the user journey, and those interruptions often correlate with abandoned sessions.

When teams work with platforms where server-side code is limited or where data must be pulled from a third party, jQuery-based asynchronous calls can still provide a pragmatic integration layer. For example, it can fetch structured content from an endpoint, then update the DOM to display it. The key is governance: teams should validate responses, handle errors, and avoid exposing sensitive data in client-side calls. That is less about the library and more about disciplined implementation.

Why it historically accelerated development.

jQuery rose because native browser APIs were once fragmented and inconvenient. At the time, developers had to write browser-specific code paths to achieve the same result, test across multiple environments, and maintain complex fallbacks. The library provided a stable abstraction layer, which effectively became a shared language across the industry. That shared language reduced team onboarding time and made tutorials, plugins, and reusable patterns widely available.

Even though many of those browser gaps have closed, the historical effect remains visible in today’s legacy estate. A large portion of business websites were built during the period when jQuery was the default choice. Those sites still drive leads, sales, bookings, and subscriptions. A rewrite might be ideal, but it is not always realistic when budgets, timelines, and operational risk are considered. A founder may prefer predictable, incremental improvements over a costly rebuild that introduces new failure modes.

This is one reason jQuery literacy still has practical value. It is less about choosing it for every new project and more about being able to confidently assess and maintain what already exists, especially in revenue-generating environments.

Where jQuery still shows up today.

Many older sites continue to rely on jQuery because it is embedded in themes, plugins, and custom scripts that were written when it was the standard. This is common across CMS-driven websites, internal tools, and long-running marketing properties that have evolved through many hands. When a team inherits such a site, jQuery is often not a “decision” so much as an existing dependency that cannot be removed without careful refactoring.

In practical terms, this means a modern stack might still contain a thin jQuery layer handling UI interactions while other parts of the site use newer approaches. For instance, a page could use server-rendered templates, sprinkle jQuery for accordions and modal windows, and rely on external scripts for analytics and tracking. That hybrid reality is typical, particularly for SMBs that prioritise stable operations and gradual upgrades.

There is also a plugin ecosystem effect. Older UI widgets, sliders, lightboxes, form enhancers, and table components frequently assume jQuery is present. Replacing them can be non-trivial because the replacement must match the existing markup, accessibility requirements, performance constraints, and styling. Teams often keep jQuery in place as a compatibility layer while selectively modernising the rest of the front end.

Maintaining legacy projects responsibly.

Legacy maintenance is not simply “keeping old code running”. It is a disciplined process of preventing regressions, improving reliability, and reducing long-term risk. Understanding jQuery helps because it enables developers to trace behaviours quickly, identify where UI logic lives, and determine whether an issue is caused by selectors, timing, event binding, or third-party plugins. This is particularly important when a small change triggers unexpected side effects, such as a form validation script blocking submissions or a menu script interfering with mobile navigation.

A sensible maintenance approach usually starts with observation and measurement. Teams can list the pages that include jQuery, inventory the plugins that depend on it, and identify critical user journeys: checkout, contact, booking, login, and account management. Once the high-impact paths are mapped, it becomes easier to decide what to refactor, what to leave alone, and what to replace. This avoids the common trap of “modernising everything” while missing the few scripts that actually drive conversions and customer satisfaction.

Refactoring can also be staged. A team might first remove duplicated selectors, replace fragile code that depends on layout quirks, and add basic error handling around asynchronous calls. Later, they might migrate isolated modules to native JavaScript or to a component-based approach. The key is maintaining behavioural parity so the business does not lose functionality during the transition.

Common pitfalls and edge cases.

jQuery code can become fragile when it relies on assumptions that no longer hold. One frequent issue is selectors that are too broad. A selector that targets “all buttons” may unintentionally affect buttons added later, breaking a new campaign banner or a checkout flow. Another issue is timing: scripts that run before content is loaded can fail silently, leading to inconsistent behaviour across pages and devices. These issues are not unique to the library, but the convenience of quick scripting can lead teams to skip structure and testing.

Plugin conflicts are also common in older sites. Two plugins may compete for the same events, or one plugin may expect a different version of the library than another. In such cases, debugging requires an understanding of how plugins attach themselves to the DOM, how they store state, and how they clean up after themselves. If they do not clean up, memory leaks and slowdowns can occur on long sessions, particularly on mobile devices with limited resources.

Performance is another consideration. jQuery operations that repeatedly query the DOM inside loops can become expensive on pages with many elements, such as catalogue grids or large FAQ pages. Caching selections, reducing repeated lookups, and limiting expensive operations during scroll events can make a noticeable difference. When performance improves, user experience improves, and search engines tend to reward that indirectly through better engagement signals.

When it is still a pragmatic choice.

Choosing jQuery today is often about constraints. If a project is small, has a tight timeline, and needs to extend a site that already includes it, it can be the most efficient tool available. It can also be appropriate when the team’s primary goal is shipping reliable improvements rather than re-architecting the front end. In these cases, the “best” tool is the one that reduces risk and delivers value quickly.

That said, responsible teams treat it as a tactical dependency, not a default strategy. They document where it is used, keep the footprint as small as possible, and avoid introducing unnecessary plugins. If modern browser APIs can solve a new requirement cleanly, they may choose those instead. The focus stays on maintainability, security, and user outcomes, not ideology.

Why the concepts still matter.

The lasting value of jQuery is not only in the code still running on millions of sites, but also in the patterns it popularised. Concise element selection, fluent chaining, and cross-browser safety shaped how many developers think about front-end ergonomics. Many modern libraries aim for similar goals: reduce boilerplate, improve readability, and make common tasks consistent.

For teams operating on platforms like Squarespace, jQuery knowledge can be especially useful because legacy templates and custom code injections often assume it. When a site needs a targeted fix, such as improving a navigation behaviour, tightening form interactions, or patching a plugin, jQuery is frequently part of the puzzle. Understanding it allows teams to move faster and avoid accidental breakage, which is critical for founders and SMB operators who cannot afford prolonged downtime.

The next step is usually deciding how to treat an existing jQuery footprint: keep it, refactor it, or phase it out. That decision becomes easier once the site’s most business-critical flows are identified and the technical debt is mapped, which leads naturally into broader conversations about modernisation and sustainable front-end architecture.

Play section audio

Why jQuery existed.

Old browser differences broke DOM consistency.

In the early era of web development, shipping the same feature across browsers could feel like shipping three different products. The Document Object Model (DOM) was meant to provide a standard tree representation of a web page, but browsers did not interpret and expose that tree in a consistent way. That inconsistency showed up everywhere: reading and writing element attributes, calculating sizes and positions, attaching events, and even deciding what “ready” meant when a page loaded.

Internet Explorer frequently diverged from Firefox, Safari, and early Chrome. A typical symptom was that a UI behaviour worked in one browser but failed silently in another, or it worked but only after quirky workarounds. Teams would end up maintaining browser-specific branches of code, which increased testing time and made releases risky. For founders and SMB owners, this translated into real business issues: support tickets from users who “cannot click the button”, abandoned checkouts caused by broken scripts, and marketing pages that did not render the same across devices and regions.

Those problems were not purely cosmetic. When a layout shifts or an element cannot be found in the DOM reliably, tracking scripts, conversion funnels, and even basic form validation can fail. That meant unreliable analytics and misattributed marketing performance, which is costly in organisations trying to make evidence-based decisions. The web needed a practical layer that could smooth those inconsistencies without every team reinventing the same fixes.

jQuery gave a unified API for common tasks.

jQuery arrived as a pragmatic abstraction. Instead of forcing developers to memorise each browser’s edge cases, it offered a single, predictable interface to do everyday work: select elements, change classes, handle events, animate UI, and send network requests. The signature idea was a compact selector-driven approach: pick the elements, then act on them with chainable methods.

That “write less, do more” approach mattered because JavaScript ergonomics were rough at the time. Many developers were building websites while also wearing design, content, and marketing hats, particularly in small teams. jQuery reduced the cognitive load by normalising common patterns. Element selection became consistent, looping over matched elements became implicit, and cross-browser quirks were handled inside the library rather than scattered across application code.

From an operational perspective, this also improved maintainability. When a team standardised on jQuery, new developers could read existing code more easily because interactions followed the same conventions. That created a shared language for front-end behaviour, which made collaboration smoother and reduced time lost in “why does this work only on this machine?” investigations.

It sped delivery while native APIs were immature.

Modern browsers now provide capable built-in tooling, but earlier native APIs were either incomplete, inconsistent, or too verbose for rapid product delivery. A key example was AJAX, which enabled websites to request data without reloading the whole page. The concept existed, but the browser implementations and the developer experience were not friendly, especially when handling varying response types, errors, and older security models.

jQuery wrapped those rough edges into simpler primitives. A developer could issue an asynchronous request, handle success and failure, and update the DOM with far fewer lines of code. For teams building dashboards, e-commerce interactions, support forms, or dynamic filtering, this made a meaningful difference. It enabled experiences that now feel normal: live search suggestions, partial page updates, inline validation, and “load more” content patterns.

Speed of delivery was not just a developer comfort benefit. It affected business outcomes. Faster iteration meant quicker experimentation with landing pages, pricing tables, signup flows, and conversion tweaks. When a team could implement and adjust interactive features in hours rather than days, it could respond to customer feedback and market movement before competitors did.

Legacy sites still depend on it.

Even though modern frameworks and browser APIs have largely reduced the original need for jQuery, it remains embedded across a large portion of the web. Many organisations have years of working code built around it, and that code often sits in revenue-critical places: storefront templates, booking flows, lead capture forms, and CMS customisations.

The practical reason is not nostalgia; it is risk management. Rewriting front-end behaviour can create regressions that are hard to predict, especially when a site has grown organically through multiple developers, plugins, and third-party scripts. For an SMB, the cost of a rewrite is not only development hours but also opportunity cost, downtime risk, and the possibility of breaking SEO-critical templates. This is why a “working” jQuery layer is frequently left in place until a major redesign or platform change justifies a broader refactor.

There is also a platform reality: many older themes, widgets, and integrations were built assuming jQuery is present. Removing it can break dependencies in subtle ways, such as event handlers that never fire or DOM modifications that run before the page is ready. As a result, jQuery often persists as an invisible but important runtime dependency.

Knowing it helps maintain legacy projects.

For developers and digital teams inheriting existing sites, understanding jQuery is still a practical skill. It helps with diagnosing issues, extending behaviour safely, and reducing the likelihood of introducing regressions. When a bug report says “the modal stopped opening” or “the checkout button does nothing on mobile”, the root cause may live in jQuery event binding, selector logic, or timing issues related to DOM readiness.

Maintenance work often involves small, high-impact changes rather than full rebuilds. Examples include updating a form flow, adding tracking events, improving accessibility attributes, or fixing a layout bug introduced by a third-party script. In those cases, jQuery knowledge enables targeted edits: adjusting selectors, replacing deprecated patterns, and isolating conflicts with newer scripts. It also supports incremental modernisation, where teams gradually replace specific behaviours with native JavaScript while keeping the site stable.

jQuery’s long history also means there is extensive documentation, community troubleshooting, and a wide ecosystem of snippets. That can be helpful when dealing with older code that lacks tests or clear ownership. The trade-off is that legacy patterns can be brittle, so disciplined changes matter: avoid globally scoped variables, limit DOM thrashing, and test across key browsers and devices after even small updates.

jQuery influenced today’s web standards.

jQuery did more than patch problems; it shaped expectations. As it became widespread, browser vendors and standards bodies had clearer signals about what developers needed most: simpler selectors, better event handling, easier DOM traversal, and reliable asynchronous patterns. Over time, many conveniences that felt “like jQuery” became part of the platform itself, such as improved selector engines and more consistent event models.

This is one reason jQuery remains relevant in a learning context. It acts like a historical map of the pain points that modern APIs were designed to solve. Understanding why jQuery’s abstractions mattered helps developers appreciate when modern equivalents are sufficient, and when legacy constraints still justify keeping jQuery in place.

Plugin ecosystems showed “extendable” design.

Another reason jQuery endured was its plugin culture. Its architecture made it straightforward to package behaviours into reusable components, then share them as drop-in enhancements. This created a practical marketplace of patterns: sliders, modals, date pickers, validation helpers, and UI effects that teams could adopt quickly.

That plugin-driven approach mirrors what many businesses still want today: adopt a capability without rebuilding a whole site. The difference is that modern ecosystems often deliver those capabilities via frameworks, components, or platform-specific extensions. On Squarespace sites, for example, that “drop-in enhancement” mindset shows up through code injection and curated plugin bundles. ProjektID’s Cx+ sits in that tradition, though it targets modern Squarespace 7.1 constraints and focuses on performance-minded UI and UX upgrades rather than the older “animate everything” era that some jQuery plugins encouraged.

Modern reality: keep, replace, or isolate.

Today, the most useful way to think about jQuery is as a legacy dependency that may still be the right tool in specific contexts. Many teams do not need to “rip it out”; they need to decide whether to keep it stable, replace it gradually, or isolate it to reduce risk. That decision depends on business goals, technical debt tolerance, and the site’s role in revenue generation.

For example, if a Squarespace marketing site uses a small jQuery script for one interaction and it has been stable for years, removing it might provide little measurable benefit. On the other hand, if a site has heavy jQuery usage that blocks performance improvements, conflicts with newer scripts, or complicates accessibility upgrades, then a phased migration to native JavaScript or a modern framework may be justified.

A practical approach many teams adopt is “strangler refactor” thinking: isolate one feature at a time, replace it with modern code, and keep the rest unchanged until it becomes the next priority. This reduces blast radius, supports continuous delivery, and keeps business operations stable while the codebase improves.

Key takeaways for digital teams.

jQuery existed because the web platform used to be inconsistent, slower to develop against, and harder to standardise. It became popular because it turned messy realities into a usable development experience and helped teams ship interactive features faster. Its continued presence is largely explained by economics and risk, not by technical preference.

Legacy support: many revenue-critical sites still rely on jQuery, directly or indirectly through themes and plugins.
Maintenance skill: teams maintaining older codebases benefit from understanding selectors, event binding, and AJAX patterns.
Modern judgement: the best path is often incremental modernisation rather than full rewrites.
Historical insight: jQuery explains why many modern native APIs look the way they do.

Once the reasons for jQuery’s rise are clear, the next step is evaluating how its patterns map to modern browser APIs and contemporary frameworks, and where it still fits when maintaining production sites that cannot be rewritten overnight.

Play section audio

Where jQuery still shows up.

Found in legacy themes and older plugins.

Across many established sites, jQuery still sits quietly in the critical path because it was once the simplest way to smooth over inconsistent browser behaviour and build interactive interfaces quickly. During its peak, themes and add-ons were routinely designed around it: developers could select elements, listen for events, animate transitions, and make network requests with compact syntax. When a site built in that era continues to generate revenue, there is often limited incentive to replace working code, so the dependency remains.

This is most visible in older templates for mainstream CMS builds and long-running marketing sites. A business might be on a modern hosting stack, yet still load a theme written years ago where the navigation, slideshow, and forms all assume a global jQuery object. Replacing that theme often means re-testing every interaction, redoing styling edge cases, and re-certifying conversions and tracking. For founders and small teams, the cost is not just developer time: it is the risk of disrupting sign-ups, purchases, or enquiry flow during a refactor.

There is also an operational reason jQuery persists: much of the older plugin ecosystem is stable, widely copied, and predictable. Many “it just works” UI patterns were packaged as drop-in scripts long before modern component libraries became common. Even when a team knows that native browser APIs can now handle many of these tasks, they may still prefer the lowest-risk option for a mature site: keep the current behaviour, fix only what is broken, and avoid introducing new moving parts.

Legacy plugin examples.

Typical older add-ons that often depend on jQuery include:

Image sliders and carousels
Modal popups
Form validation scripts
Dynamic content loaders

These components are frequently “foundational” because they sit in high-visibility areas: hero sections, product galleries, lead-capture forms, and promotional overlays. An image slider, for example, is rarely just decoration. It may drive clicks into best-selling collections, rotate seasonal offers, or act as a visual explanation of a SaaS workflow. That business value makes teams reluctant to swap it out unless the replacement is proven, accessible, and performance-tested.

Many of these plugins have also been tuned repeatedly over time, including small bug fixes for touch events, layout quirks, and timing issues. That history can make a legacy jQuery plugin more reliable in practice than a brand-new rewrite, even if the rewrite is “more modern” on paper. The trade-off is that these plugins can become opaque: if a bug emerges, a team may end up debugging minified code that no current developer truly “owns”.

Present in older CMS customisations.

In long-running CMS builds, custom scripts often lean on DOM manipulation patterns that were standard when the site was first assembled. A developer might have added interactive filtering, conditional field logic, UI toggles, or dynamic content injection using jQuery because it was quick to implement and easy to reason about at the time. Those scripts then persist across redesigns, sometimes copied forward into new templates without a full review.

This is common in community-heavy platforms where snippets travel from forum posts to production sites. A small business may have added “just a little script” years ago to improve menu behaviour, hide empty blocks, or adjust form states, and that script may still run on every page. Often, nobody remembers it is there until it conflicts with a new feature, breaks after a platform update, or causes subtle performance issues on mobile.

jQuery also remains popular in older customisations because it lowered the barrier to entry. Developers could implement interactive behaviour without deeply understanding browser APIs, event propagation, or edge cases such as NodeLists versus arrays. That historical convenience is still attractive in teams where web work is shared across marketers, ops, and part-time developers who prioritise shipping improvements over re-architecting.

Community code examples.

Common community-style customisations that frequently involve jQuery include:

Custom widgets for sidebars
Enhanced navigation menus
Dynamic content filters
AJAX-based content loading

Each example maps to real-world goals. Dynamic filters help users find services, case studies, or products faster, which supports conversion. Background loading can make a catalogue feel responsive and “app-like”, particularly when users move between categories quickly. Enhanced menus often reduce friction on complex sites by surfacing deeper pages without forcing multiple page loads. The practical benefit is clear, so teams keep the code even if the implementation is dated.

That said, these improvements can come with hidden costs. Poorly implemented background loading can break analytics attribution, confuse screen readers, or create inconsistent back-button behaviour. Menu scripts can conflict with platform updates or accessibility requirements if focus states and keyboard navigation were not handled properly. These are not reasons to panic, but they are reasons to periodically audit what scripts exist, what they do, and whether they still match today’s expectations.

Some platform ecosystems include it.

Several hosted platforms still ship with or commonly expose jQuery in ways that make it easy to use, including Squarespace and other builders where code injection is a supported pattern. This matters because it influences “how” site owners solve problems. If the platform already loads jQuery, many people will reach for it first when adding interactive features, because it feels like the shortest path from idea to outcome.

Platform inclusion also shapes the available template and snippet ecosystem. If many themes assume jQuery is present, the shared community solutions will reflect that assumption. A founder looking for a quick improvement to navigation or a product gallery might find a ready-made snippet that relies on jQuery simply because that was the dominant approach when the snippet was written and circulated.

The key point is that “included by default” does not automatically mean “best choice today”. It means it is available, familiar, and compatible with a wide range of existing add-ons. Technical teams often treat this as a legacy compatibility layer: useful when maintaining older features, but not necessarily the preferred base for new development if performance, maintainability, or long-term migration is a concern.

Examples of platforms including it.

Platforms where jQuery is commonly encountered include:

Squarespace
Shopify
WordPress
Wix

On these platforms, templates often contain interactive components built during periods when jQuery was the default tool for UI enhancement. This makes it easy for less technical teams to implement common behaviours quickly. It also means a site can accumulate scripts over time from multiple sources: a theme, a third-party add-on, and a few “small” code injections added during campaigns.

For operational teams, the practical move is visibility: keep a simple inventory of scripts, where they are loaded, and which pages rely on them. When performance dips or a feature breaks, that inventory prevents costly guesswork. It also supports better decision-making when a team considers moving from legacy snippets to modern equivalents.

Often used for quick fixes.

When teams need a small behavioural change immediately, code injection areas invite quick jQuery snippets because they can be pasted in and tested fast. Typical use cases include minor UI tweaks, lightweight animations, and “glue code” that connects an interaction to an existing page element. In fast-moving businesses, this can be the difference between shipping a campaign today versus waiting two weeks for a deeper rebuild.

A smooth scroll effect for anchor links is a common example: it improves perceived polish, especially on long sales pages. Another is attaching basic state to a button or banner, such as hiding a notice after a click. In many cases, these are pragmatic choices, not architectural ones. The organisation is optimising for speed of delivery, and jQuery can still deliver that speed.

However, quick fixes can become permanent. When a snippet solves a problem, it tends to stick around through redesigns, migrations, and staffing changes. Over time, a site can accumulate overlapping behaviours: two scripts listening for the same event, or a new section layout that breaks an older selector. A healthy practice is to treat injected scripts like any other production dependency: document them, version them when possible, and retire them when their purpose disappears.

Common quick fix scenarios.

Frequent “fast patch” uses include:

Implementing smooth scrolling
Creating toggle menus
Adding dynamic content updates
Handling form submissions without page reloads

These scenarios highlight why jQuery stuck: the mental model is straightforward. Select the element, bind the event, update the DOM. On a busy marketing site, that simplicity can be valuable. Yet the same simplicity can conceal complexity, especially around accessibility, performance, and cross-device behaviour. For example, a toggle menu needs keyboard support, correct focus management, and sensible ARIA attributes to avoid excluding users. jQuery can implement all of that, but most quick snippets do not.

A practical compromise is to use jQuery as a stabiliser, not a crutch. If a snippet is mission-critical, teams can harden it: add guards if elements are missing, ensure it only initialises once, and measure its impact on page performance. If it is not critical, teams can remove it when a platform-native feature or modern script replaces it cleanly.

Common in long-lived projects.

Projects with a long maintenance history often retain jQuery because it is deeply woven into the site’s behaviour and team habits. In these environments, the real constraint is rarely “can it be rewritten?” It is “can it be rewritten without breaking revenue flow?” A mature site tends to contain edge case logic that exists for a reason: a workaround for a browser quirk, a specific checkout interaction, or a compatibility fix for a third-party tool.

When developers rotate in and out, jQuery becomes part of the inherited system. New maintainers may avoid changing what they do not fully understand, especially if the original authors are gone and tests are limited. This can lead to a stable but ageing codebase where improvements happen as patches, not as modernisation. The risk is technical debt: each new feature might require more time because the system is harder to reason about.

Long-term jQuery reliance can also complicate the adoption of newer approaches. Modern component frameworks and build tooling tend to expect a module-based structure, predictable state management, and clear boundaries between components. jQuery scripts, especially those added incrementally, can be globally scoped and tightly coupled to specific HTML structures. That coupling makes refactors more delicate and increases the chance of regressions.

Challenges of long-term jQuery projects.

Common challenges in long-lived jQuery-based builds include:

Difficulty in integrating modern frameworks
Potential for code bloat and complexity
Increased maintenance costs
Dependency on outdated libraries

From a business perspective, these challenges translate into slower iteration cycles, higher risk when deploying changes, and greater reliance on specialists who understand the legacy patterns. Teams can reduce that risk with gradual migration rather than a “big rewrite”. That often means isolating new features away from legacy scripts, replacing one plugin at a time, and introducing a lightweight testing approach around revenue-critical flows.

Technical debt is not simply “old code”. It is code that costs more to change than it should. When jQuery is part of that debt, the decision is rarely binary. Many organisations succeed by keeping jQuery where it is stable and valuable, while prioritising modern patterns for new work. The next step is to look at how to evaluate whether a jQuery dependency is harmless, helpful, or actively holding back performance and maintainability.

Play section audio

When not to use it.

When modern native APIs cover the need cleanly.

In many projects, jQuery is no longer the shortest path to reliable functionality because modern browsers now ship with strong built-in interfaces for the same jobs. What jQuery originally “fixed” was inconsistency: different browsers exposed different event models, selection rules, and network behaviours. Today, evergreen browsers have converged around shared standards, so teams can often achieve the same outcome with less dependency surface and fewer moving parts.

A clear example is network calls. The fetch API covers most request patterns with readable, promise-based syntax, and it pairs naturally with modern async code. For DOM selection and traversal, querySelector and querySelectorAll provide CSS-selector-powered element lookup that is both expressive and familiar. Once those primitives are in place, many of jQuery’s “quality of life” helpers become optional rather than essential.

Native code can be simpler than a dependency.

Examples of native API replacements.

fetch(url) instead of $.ajax()
document.querySelector('.className') instead of $('.className')
element.classList.add('new-class') instead of $(element).addClass('new-class')

Where native APIs become especially appealing is long-term maintenance. A site that relies on standards tends to stay compatible as platforms evolve, because browser vendors treat those interfaces as foundational. By contrast, using a library for tasks the platform already does well can create a dependency that must be tracked, audited, and occasionally replaced, even if the application only needs a fraction of its capability.

There are still edge cases where jQuery appears convenient, such as quick one-off scripts for older templates. Even then, teams benefit from checking whether a small utility function or a few well-chosen native calls would be easier to explain, test, and keep stable over time.

When it adds unnecessary weight and complexity.

Even a “small” library becomes expensive when it is loaded on every page and becomes a habitual default. The issue is rarely just file size; it is the broader overhead: a new dependency to patch, an extra global API surface, and a tendency for code to drift into patterns that only make sense when that library is present. For performance-sensitive sites, particularly those targeting mobile traffic, the cumulative effect can show up as slower first loads and longer time-to-interactive.

It often starts innocently: a single jQuery helper is added for a dropdown, a class toggle, or a minor animation. Then other scripts begin to assume jQuery exists, and soon the project depends on it everywhere. At that point, removing it becomes more difficult than adding it was, because the dependency is woven into everyday development. This is one reason many teams now adopt a “native first” rule: use built-in APIs unless there is a demonstrated gap.

Considerations for weight and complexity.

Evaluate the size of jQuery against the project requirements.
Assess whether the same features can be implemented with native code.
Consider the impact on load times, especially for mobile users.

In a practical workflow, “evaluate” should mean more than guessing. Teams can measure real impact using browser devtools: check total transferred bytes, run a performance profile, and compare a jQuery-driven interaction against a native implementation. If the only requirement is DOM selection and a few class toggles, native code usually wins on simplicity, and it reduces the chance of a dependency-related breakage later.

There is also an operational angle. When a dependency is introduced, it must be approved, versioned, and monitored for security advisories. For small businesses and lean product teams, this governance can be the hidden cost. Keeping the dependency list short is not just an engineering preference; it is a way to reduce ongoing work.

When mixing patterns complicates maintenance.

Mixing DOM-manipulation approaches often creates bugs that feel “random” because the application ends up with multiple sources of truth. Modern UI frameworks such as React and Vue typically assume they control the DOM they render. When another tool reaches into that same DOM and changes it directly, the framework may overwrite those changes on the next render cycle, or worse, it may preserve them in one place but not in state, creating subtle inconsistencies.

This is not about jQuery being “bad”; it is about mental models. Frameworks encourage declarative UI: state changes, and the UI updates as a result. jQuery code often operates imperatively: find an element and change it now. When both exist in the same system, developers have to remember which parts are safe to touch and when, which raises the cognitive load and increases the probability of regressions during routine updates.

Best practices for maintenance.

Stick to one paradigm for consistency.
Document any jQuery usage within a framework context.
Train team members on the implications of using multiple libraries.

When a team inherits a mixed codebase, the most stable approach is usually to draw boundaries. For example, legacy pages might keep jQuery, while new feature work in a framework avoids it completely. Another common pattern is to isolate imperative scripts to non-reactive areas such as marketing content pages, while product flows remain fully inside the framework’s control. The key is predictable ownership of the DOM.

For teams working in platforms like Squarespace, pattern mixing can happen unintentionally. A template might include old snippets, while new code uses modern techniques. In that situation, an inventory of scripts and their responsibilities is often the fastest way to regain stability. Even a simple list of “what runs where” can reduce debugging time dramatically.

When performance is critical on mobile devices.

Mobile performance constraints are not theoretical. Many users browse on mid-range phones, under battery-saving modes, and on inconsistent networks. When an interaction relies on heavy scripting or repeated DOM manipulation, it can lead to dropped frames, delayed taps, and layouts that shift unexpectedly. For animation work in particular, jQuery can encourage patterns that are less aligned with modern rendering pipelines.

When a site animates via CSS transitions or transforms, browsers can often offload work to more optimised rendering paths. That typically results in smoother motion and fewer “janky” interactions. By comparison, script-driven animations can end up recalculating layout frequently, especially when they change properties that trigger reflow. The outcome is visible: scrolling stutters, menus feel sluggish, and the interface seems heavier than it needs to be.

Performance tips for mobile.

Use CSS for animations whenever possible.
Minimise DOM manipulations during animations.
Test performance on various mobile devices to ensure a smooth user experience.

Mobile performance is also affected by how often scripts run. A common edge case is attaching too many event handlers (scroll, resize, touchmove) and doing expensive work in each callback. Whether the code is jQuery or vanilla JavaScript, this can degrade responsiveness, but jQuery makes it easy to add handlers broadly without noticing the cumulative cost. A more defensive approach is to limit high-frequency handlers, debounce where appropriate, and prefer passive listeners for scroll-related work when the browser supports it.

Teams that rely on conversion flows (booking, checkout, lead capture) usually benefit most from this discipline. A fast, stable mobile experience is often a direct revenue lever, because it reduces abandonment during high-intent moments.

When the team isn’t aligned on its use.

Tool choice is partly technical and partly organisational. If a team is split between jQuery and native or framework-driven approaches, the codebase tends to fragment: some components follow one style, others follow another, and the overall system becomes harder to reason about. That fragmentation slows delivery because engineers spend time translating between approaches, and it makes onboarding more difficult because new contributors cannot rely on a consistent set of patterns.

Alignment does not require everyone to “love” the same tool, but it does require shared rules. A team might decide that jQuery is permitted only in legacy sections, or only for a specific plugin that depends on it, or only until a defined migration milestone is met. Without those boundaries, jQuery can become an accidental default, and every future improvement inherits that inconsistency.

Strategies for team alignment.

Conduct training sessions on jQuery and its use cases.
Establish coding standards that dictate when to use jQuery.
Encourage open discussions about the pros and cons of using jQuery in projects.

It also helps to make the decision measurable. For instance, a team can agree to prefer native APIs when browser support matches the audience, and to document any exceptions in a short architectural note. This reduces opinion-based debate and replaces it with repeatable decision-making. Where teams manage multiple client sites, this kind of policy is especially useful because it prevents each project from drifting into a different set of conventions.

How to decide in modern projects.

The broader context is that web development has shifted from patching browser quirks to composing systems. Modern frameworks provide state management, routing, component architectures, and build tooling, which means jQuery’s original role is smaller in many stacks. Meanwhile, contemporary JavaScript language features make code more expressive and maintainable without extra abstractions.

From a decision standpoint, jQuery still makes sense in a narrow set of scenarios: legacy applications where it is already deeply integrated, situations where rewriting would introduce more risk than benefit, or environments where a specific dependency requires it. Outside those cases, teams usually get better outcomes by leaning on platform APIs and specialised libraries that focus on one concern. For example, rather than using a general-purpose library for network calls and animation, teams might reach for a dedicated HTTP client or a high-performance animation engine when those needs are real and proven.

Relevance depends on context, not nostalgia.

A pragmatic approach is to run a quick decision checklist before introducing jQuery into a new codebase:

Confirm the feature cannot be met cleanly with native APIs and light utilities.
Identify whether a modern framework already provides the needed mechanism.
Estimate the long-term cost: dependency updates, onboarding, consistency, and security review.
Validate performance impact on mobile, not just on a developer laptop.

When teams apply that discipline, jQuery often becomes a “legacy compatibility” tool rather than a default dependency. That change in mindset helps reduce technical debt and improves the reliability of day-to-day delivery.

In the next section, the focus can shift from “when not to use it” to the few scenarios where it still earns its place, including how to manage legacy jQuery responsibly while modernising a site or application incrementally.

Play section audio

Common tasks.

jQuery simplifies DOM work.

jQuery is a JavaScript library built to reduce friction in everyday front-end work, particularly when a page needs to find, update, create, or remove elements. Instead of writing verbose browser APIs, developers can express intent in a compact pattern: select something, then act on it. That “select then transform” mental model matters in real projects because most UI behaviour is essentially a loop of small DOM changes triggered by user input, page state, or data coming from elsewhere.

A practical example is a marketing site running on Squarespace where a team wants to adjust a banner message based on whether a visitor has dismissed a notice. With native JavaScript, that can mean multiple calls to query selectors, classList operations, conditional checks, and careful handling of null references. In jQuery, selection and manipulation become a short chain, which speeds up iteration when changes are frequent or when multiple contributors touch the code.

That simplicity becomes even more valuable on older sites or long-lived client projects where a mixture of code styles exists. Many legacy pages were written before modern browser APIs became consistent across vendors, and jQuery’s abstraction helped keep behaviour stable even when browsers disagreed about edge cases. While modern JavaScript has improved a great deal, jQuery still shows its strength when a team needs to maintain or extend an existing codebase without refactoring everything.

Key features for DOM manipulation.

CSS-like selectors to target elements quickly and readably.
Chainable methods that keep related actions together.
Normalised behaviour across browsers, helpful on legacy builds.
Convenient helpers for attributes, styles, and HTML or text content.

It streamlines events and AJAX.

Interactive sites live and die by how reliably they respond to user actions. jQuery’s event system makes it straightforward to attach handlers for clicks, keypresses, scroll behaviour, and form submissions without constantly thinking about browser quirks. It also supports patterns such as event delegation, where a single handler can manage interactions for many child elements, including elements that are injected later.

Event delegation is especially useful on dynamic pages, such as product listings or filtered directories. For example, an e-commerce category page might re-render product cards after filters change. If a team attaches click handlers to each card individually, those handlers may disappear when the DOM is replaced. Delegation solves that by attaching a handler once to a stable parent and checking what was clicked. The result is fewer bugs, less duplicated code, and behaviour that survives dynamic updates.

Alongside events, jQuery’s built-in support for asynchronous requests made it a default choice for loading data without refreshing the page. AJAX workflows allow a page to fetch new content, submit forms, and update UI state in the background. Even though the modern Fetch API is now standard, many production systems still use jQuery’s methods because they are already wired into the existing application logic and error handling.

In practical operations work, this often shows up when a team needs to connect a form to an automation tool such as Make.com, or to a lightweight backend running on Replit. jQuery can collect form values, send them to an endpoint, then update the UI with success or failure feedback, all without a full page load. Done well, that improves perceived performance and reduces abandonment on multi-step flows.

Benefits for event handling and AJAX.

Simplified syntax for binding common events.
Predictable behaviour across browsers, particularly older ones.
Fast asynchronous updates for content, forms, and UI state.
Support for custom events and delegation patterns.

jQuery syntax stays concise.

A major reason jQuery became widely adopted is that it compresses common patterns into a readable shorthand. This is not only about writing fewer characters. It is about reducing the surface area for mistakes: fewer repeated selector calls, fewer manual loops, and fewer lines where null values can cause runtime errors. In teams with mixed technical confidence, concise code can also lower maintenance cost because intent is easier to scan.

For example, hiding an element can be expressed as $(‘#element’).hide();. Behind that one line, the library handles selection, internal iteration, and style updates. The same principle applies to toggling classes, inserting content, and reading values from inputs. The result is a style of scripting that suits quick experiments and incremental improvements, which is common for founders and small teams who optimise pages over time rather than rebuilding everything in one sprint.

Conciseness has a trade-off. Because chains can become long, teams can accidentally create “do everything” statements that are hard to debug. A healthy approach is to keep chains short, store intermediate selections when reused, and name intent in small functions. That preserves the “write less” advantage while keeping code review and troubleshooting realistic in a busy operations environment.

Examples of concise syntax.

$(‘.class’).fadeIn(); Changes visibility with a fade effect.
$(‘#id’).toggle(); Toggles the display state.
$(‘p’).css(‘color’, ‘blue’); Updates paragraph text colour.

It boosts UX with animations.

Visual transitions can make interfaces feel more understandable because they show state change rather than snapping abruptly. jQuery includes a set of animation helpers that are simple to apply, such as fades and slides. These effects are often used to reveal help text, expand FAQs, confirm actions, or guide attention towards a call-to-action without redesigning the whole layout.

For example, a service business site might hide long policy text behind a “Read more” interaction. With a slide animation, the user sees that the content exists and expands in place, making the interaction feel intentional. Used sparingly, these micro-interactions can increase clarity and reduce cognitive load, especially on mobile where space is limited and long pages become tiring.

Performance still matters. Modern best practice often prefers CSS transitions for smoothness and GPU acceleration, yet jQuery remains common in older builds where the animation logic is tied to event handling or where multiple effects are chained in a specific order. Teams maintaining legacy client sites frequently keep jQuery animations because they are predictable, already tested, and less risky than swapping out the entire interaction model.

Advantages of jQuery animations.

Fast to implement without building a full animation framework.
Chaining enables multi-step transitions with clear sequencing.
Consistent behaviour across browsers for older projects.
Easy pairing with events to create interactive UI patterns.

The plugin ecosystem extends capability.

jQuery’s reach expanded because developers could package reusable behaviours as plugins. Instead of building every carousel, modal, table sorter, or validation routine from scratch, teams could adopt a plugin, configure it, and move on to project-specific logic. For small businesses and agencies, this historically reduced build time and helped deliver polished features with limited development resources.

Plugins can still be valuable when a site is locked into an older stack or when upgrading would cost more than it returns. A long-running Squarespace site, for instance, may have custom scripts layered over time. If the site already depends on jQuery, a well-chosen plugin can solve a specific need, such as improving table readability or adding lightweight validation, without introducing a completely new framework.

That said, the plugin approach requires discipline. Poorly maintained plugins can cause security and performance issues, and some older packages assume outdated browser behaviour. Teams get the best outcome by selecting plugins with clear documentation, recent updates, and a realistic footprint. Where possible, plugins should be loaded only on pages that need them, so they do not slow down the entire site.

Popular plugins include.

jQuery UI for interface interactions, effects, and themes.
DataTables for adding search, sorting, and pagination to tables.
Lightbox patterns for displaying media in modal overlays.
jQuery Validation for client-side form rules and messages.

Beyond the usual favourites, specialised tooling has often been built around mobile behaviour and form processing. For example, jQuery Mobile historically provided a framework for touch-friendly UI patterns, while jQuery Form simplified serialisation and asynchronous submission. Even when teams no longer start new projects with these libraries, they remain relevant in maintenance work, which is a major part of real-world delivery.

Plugin ecosystems also influence internal workflow. When teams use no-code or low-code systems such as Knack for data-driven apps, they often embed custom front-end logic for polish, validation, or conditional display. A plugin can save time, but only if it aligns with the project’s constraints, such as content security policies, performance budgets, and the ability of a non-specialist to maintain it later.

Best practices for plugins.

Choose maintained plugins with active issue tracking and clear documentation.
Test compatibility with the existing codebase and hosting environment.
Keep versions updated to reduce security and stability risks.
Measure performance impact, especially on mobile networks.

Where jQuery still fits today.

jQuery is no longer the default recommendation for brand-new, complex applications, mainly because modern frameworks and browser APIs cover many of the same needs. It still holds a meaningful place in the ecosystem because the web has a long memory: countless production sites rely on it, and replacing it is often riskier than keeping it stable. That is particularly true for revenue-generating sites where the cost of regression outweighs the benefit of modernising.

It also remains useful for rapid prototyping and targeted enhancements. A growth manager might want to test a new interaction on a landing page, or an operations lead might need to improve a form flow quickly. Adding a small, well-scoped jQuery script can be a pragmatic move, as long as it is documented and does not become an uncontrolled dependency.

Modern JavaScript covers much of the gap.

Teams evaluating whether to keep or remove jQuery tend to compare it against native APIs such as querySelector, classList, and fetch. Modern JavaScript can be just as capable, but the migration cost is not only technical. It includes regression testing, reworking plugins, retraining contributors, and validating cross-browser behaviour for the audience the business actually has. A sensible approach is often incremental: keep jQuery where it already solves a problem, and use native patterns for new code when practical.

From an SEO and performance perspective, the biggest risk is usually not jQuery itself but uncontrolled script growth. Multiple plugins, duplicated libraries, and page-wide animations can increase load time and degrade interaction metrics. The fix is governance: audit scripts, remove what is unused, load conditionally, and keep behaviours tied to measurable outcomes such as reduced form abandonment or higher conversion rates.

Technical depth: asynchronous patterns.

jQuery introduced tools to structure asynchronous behaviour, including Deferred objects and Promise-like flows. This matters when several background operations must run in order, such as loading configuration, then fetching content, then updating UI state. While modern Promises and async or await are now standard, many legacy codebases still rely on these jQuery patterns. Understanding them helps teams debug “it works locally but not in production” issues that arise from timing, race conditions, or error handling that silently fails.

When maintaining such systems, a practical technique is to wrap older deferred flows with a consistent error pathway and logging, so failures surface quickly. That can be done without rewriting everything, which is often the most business-friendly option for SMB teams balancing delivery, budget, and reliability.

If this section has framed jQuery as a pragmatic maintenance and iteration tool, the next step is to examine how teams can decide between legacy libraries and modern frameworks, based on audience needs, performance targets, and the true cost of change.

Play section audio

Selectors and event handling.

jQuery remains popular because it compresses two everyday jobs into a readable pattern: finding elements and reacting to user actions. When those jobs are handled with intent, pages feel faster, bugs are easier to isolate, and teams can maintain scripts without “mystery selectors” or duplicated event handlers.

This section expands practical selection and event-binding strategies that reduce performance drag, avoid accidental side effects across the DOM, and make behaviour predictable even when content is injected dynamically by CMS blocks, AJAX calls, or front-end frameworks layered onto Squarespace, Knack, or custom builds.

Select elements without broad selectors.

Element selection is the first decision that affects both performance and correctness. A selector that matches too much creates two problems: it forces unnecessary DOM work and it increases the chance that the code alters the wrong elements. Pages with heavy layouts, large product catalogues, or nested CMS blocks feel this immediately because selection runs repeatedly, often inside scroll, resize, or click handlers.

The most common anti-pattern is the global selector that effectively says “touch everything”. For example, selecting all nodes can turn a small styling change into a full DOM sweep, which becomes expensive as the document grows. That cost is not just theoretical; it shows up as sluggish interactions, delayed animations, and click handlers that feel “sticky” on mobile devices.

Specificity is the simplest fix. IDs, classes, and attribute selectors narrow the search space so the browser returns a smaller, more accurate set. For example, selecting a known class on a known container is typically faster and safer than selecting the class across the entire page. Beyond speed, targeted selectors make intent obvious during code review, which matters when multiple contributors ship updates over time.

On content-managed sites, specificity should account for repeated components. Squarespace sections, product grids, or blog lists often reuse the same internal class names. In those scenarios, selecting within a container avoids unintentionally affecting multiple instances. A reliable pattern is scoping selections with a parent reference so only the intended block is touched.

Prefer stable hooks. Use dedicated classes meant for scripting, rather than styling-only classes that designers may rename.
Scope to a container. Select inside a known region to avoid collisions across repeated layouts.
Avoid unnecessary traversal. Deep selectors like “this inside that inside that” can be fragile when markup shifts.

Where performance matters, caching also helps. If a script selects the same element repeatedly, storing the jQuery object in a variable prevents repeated lookups. This is especially useful in plugins or site-wide enhancements where the same element is referenced across multiple interactions.

Attach events safely without duplicates.

Event binding looks simple, yet duplicated handlers are one of the most common causes of “double submits”, repeated animations, and inconsistent state. This often happens when scripts run more than once, such as after partial page renders, modal opens, CMS content loads, or when multiple scripts target the same selector independently.

A practical defensive pattern is to remove a handler before reattaching it. The key tool is .off(), which detaches existing handlers, followed by binding again. This ensures the click, submit, or change behaviour runs once per interaction rather than stacking invisibly with every reinitialisation.

Example pattern:

Note: The code examples below are illustrative patterns; implementations should align with the site’s quoting style and linting rules.

Remove then add:

$(‘#myElement’).off(‘click’).on(‘click’, function() { /* handler code */ });

This approach works well when there is a single known element. When multiple modules share the same nodes, namespacing provides stronger safety. Event namespaces allow code to remove only the handlers it owns, instead of wiping out unrelated behaviour. This avoids accidental breakage in larger codebases.

Use event namespaces. Bind with “click.moduleName” and remove with the same namespace to avoid collateral removal.
Bind once when possible. Initialise handlers on document ready and rely on delegation for dynamic children.
Avoid binding inside other handlers. Binding a click handler from within a click handler is a fast route to duplication.

Another subtle duplication source is binding during responsive breakpoints. If a script binds mobile-specific behaviour on resize without unbinding previous handlers, each breakpoint crossing can add new handlers. A simple guard is to track state, or to rebind cleanly using a namespace each time a breakpoint changes.

Use delegation for dynamic elements.

Modern pages rarely have static markup. Product cards may load after filtering, blog entries may appear through infinite scroll, and embedded systems like Knack can render views after authentication. Directly bound handlers only attach to elements that exist at binding time, which means newly added elements will appear “dead” unless the binding is repeated.

Event delegation solves that by binding to a stable ancestor and listening for events that bubble up from matching descendants. This keeps code simple and resilient, because the handler is bound once, yet it still reacts to elements injected later.

Example delegation pattern:

$(‘#parent’).on(‘click’, ‘.child’, function() { /* handler code */ });

Delegation also improves performance when there are many similar elements. Instead of binding hundreds of click handlers to hundreds of items, one handler can serve them all. That matters on catalogue pages, directory listings, or table-heavy admin interfaces where each row may otherwise get its own handler.

Delegation has limits, and being aware of them prevents edge-case bugs:

Not all events bubble. Some events behave differently across browsers, so testing matters for focus-related interactions.
Stop propagation carefully. If a child handler stops bubbling, delegated listeners higher up may never fire.
Choose a stable ancestor. Binding to “body” works, but binding to a nearer container reduces event traffic.

For UI components that frequently re-render, delegation often becomes the default. It is particularly useful where a Squarespace page section is replaced by injected HTML, or when a Make.com automation updates a view via a webhook-triggered render and the DOM nodes are regenerated.

Keep chaining readable using context.

Chaining is one of the reasons jQuery code can read like a set of steps. A chain works because each method returns a jQuery collection, so the next call continues to operate on the same set. When used cleanly, chaining reduces temporary variables and groups actions by intent, which helps maintainers see “what happens to this element” in one place.

The risk appears when the selection context changes mid-chain without being obvious. Methods such as traversal helpers can alter which nodes are in the current set, and the script may start modifying siblings or parents when it meant to keep operating on the original element. That creates bugs that are hard to spot because the chain still “looks” correct at a glance.

Example of a simple, clear chain:

$(‘#myElement’).addClass(‘active’).fadeIn(500).css(‘color’, ‘red’);

A maintainable chaining style relies on two habits:

Chain only related operations. Visual changes, accessibility tweaks, and state updates can sit together when they apply to the same node set.
Break the chain when context shifts. If traversal changes the selection, store it in a named variable to make the shift explicit.
Prefer intention-revealing naming. A variable like “$menuItems” communicates scope better than “$el”.

Chaining readability becomes more important in mixed-ownership environments, such as websites where marketing adjusts layout while operations maintain scripts. Clear scoping and explicit context changes reduce the chance that a small content edit breaks interactive behaviour.

Debug multiple handlers and bubbling.

When a click fires twice, or when a modal closes immediately after opening, the cause is often multiple handlers or unexpected event bubbling. Debugging is easier when the approach is systematic: isolate the handler, confirm how many times it binds, then check propagation through the DOM tree.

A simple isolation step is to temporarily remove handlers and add a minimal logger. Using console.log inside a single handler confirms whether the event is firing once and which element is actually receiving it. For example, removing all handlers on the element and re-binding a simple click can reveal whether the bug lives in a second script, a delegated parent listener, or a repeated initialisation routine.

Minimal isolation pattern:

$(‘#myElement’).off().on(‘click’, function() { console.log(‘Clicked!’); });

From there, it helps to inspect propagation. Many “mystery clicks” happen because a click on a button also triggers a click listener on a parent card, which might navigate away, close a dropdown, or submit a form. In those cases, stopping propagation at the right level can prevent side effects, but it should be used deliberately. Overusing propagation control can block legitimate behaviours, especially when other components rely on bubbling for delegation.

Confirm binding count. If the log prints twice per click, the handler is duplicated.
Check delegate ancestors. A parent “on click” may be catching child clicks unintentionally.
Audit reinitialisation triggers. Scripts that run on AJAX load, modal open, or route change often rebind.

In more complex builds, browser devtools can help trace listeners, but the core idea remains the same: reduce the surface area until the behaviour becomes predictable, then reintroduce complexity step by step. That discipline is especially valuable when multiple plugins, third-party widgets, and custom scripts coexist.

With selectors and event handling under control, the next step is usually to look at how data and state are managed between interactions, particularly when multiple UI components share the same information or need to stay in sync.

Play section audio

DOM updates.

Managing the Document Object Model (DOM) efficiently sits at the heart of responsive, modern web experiences. When an application feels “snappy”, the code is usually doing less work in the browser’s rendering pipeline, not merely running faster JavaScript. Tools like jQuery can still play a practical role in many legacy sites and fast-moving SMB environments, especially where teams maintain Squarespace customisations, lightweight marketing sites, or internal tools that need dependable DOM manipulation without rebuilding everything in a new framework.

This section explains how to update content while reducing layout churn, how to construct elements in a safer way than dumping strings of HTML, how to remove UI parts without leaving behind memory leaks, how to manage UI state with predictable class patterns, and how to avoid repeated “init” loops that quietly degrade performance over time. These techniques matter for SEO and UX because slow, janky interfaces increase bounce, reduce time-on-page, and often lead to more support requests when users cannot find or complete actions.

Updating content without triggering layout storms.

Many performance problems do not come from “heavy code”, but from repeatedly forcing the browser to recalculate layout and repaint the page. Each time the page layout changes, the browser may need to run a layout pass, paint pixels, and composite layers. A single change might be cheap; a hundred small changes in quick succession can become visibly jarring.

Reflow (also called layout) occurs when a DOM change affects size or position, so the browser must recalculate geometry. Repaint occurs when pixels change but layout does not. Developers can reduce both by batching DOM writes, avoiding patterns that alternate reading layout values and then writing new ones, and by delaying visual updates until the final state is ready.

In practice, batching means preparing changes in memory and applying them in a single DOM operation, rather than repeatedly calling .append(), .html(), or .css() inside loops. For example, when rendering a list of search results or product cards, a team can build a set of nodes first and then append once. jQuery supports this approach by letting developers create detached elements and append them together, which reduces layout recalculations.

Another common optimisation is “visibility gating”. Instead of making five changes to an element that is currently visible, the element can be hidden, updated, then shown. This limits how many intermediate states the user sees and can reduce the browser’s work. The underlying idea is not that hiding is magic, but that intermediate paints become less likely to matter visually. This is especially helpful with complex components like accordions, navigation menus, and pricing tables where many sub-elements change at once.

Batching style changes also matters. Changing multiple CSS properties one-by-one often triggers multiple recalculations, while applying them in a single call gives the browser a better chance to optimise. With jQuery, applying multiple properties as an object keeps code clean and reduces “death by a thousand writes”.

Prefer building the final state first, then apply it once.
Avoid alternating “measure then mutate” repeatedly in the same frame.
Apply multiple CSS changes in a single operation where possible.
Hide, update, and show when several changes must occur quickly.

Edge case to watch: frequent updates from timers, scroll handlers, or resize handlers can unintentionally trigger constant layout work. If a page updates a header position on every scroll event and also measures element width inside the same handler, performance will drop quickly on lower-end devices. In those cases, throttling or debouncing, plus separating reads from writes, often makes the biggest difference even before changing any UI design.

For teams using Squarespace code injection or embedded scripts, this matters because the site’s base theme already runs its own layout and animation logic. Heavy DOM churn from custom scripts can compete with the platform’s scripts and cause stutter that is difficult to diagnose.

Building elements safely, not dumping strings.

When adding new UI pieces, developers typically choose between creating nodes via JavaScript or inserting raw HTML strings. Raw HTML injection can feel faster to write, but it carries risk and maintenance cost, particularly when any part of the string can be influenced by external data such as form inputs, CMS content, URL parameters, or third-party APIs.

The biggest risk is cross-site scripting (XSS), where attacker-controlled content is injected and executed as code in the browser. Even when a team believes content is “trusted”, content pipelines change. A business may later syndicate reviews, import product descriptions, or integrate with an automation tool like Make.com that inserts data into pages. If string injection is the default pattern, the site becomes fragile.

Creating elements via jQuery’s API is often safer because it encourages separation of structure from content. Text can be inserted with .text() (which escapes HTML), while attributes can be set explicitly. This makes it much harder for a random “<script>” tag to slip into the DOM unnoticed. It also supports clearer intent: content is content, markup is markup.

When HTML parsing is genuinely required, jQuery offers $.parseHTML() to convert a string into nodes. It is not a silver bullet, but it provides a controlled step where sanitisation and filtering can be applied before insertion. This is a better pattern than directly pushing unknown HTML into .html().

Practical rule: if the content originates from a user, a CRM, a spreadsheet import, or any system that could be edited without code review, treat it as untrusted. Insert it as text, or sanitise it with a well-maintained sanitiser before allowing HTML. The “clean” approach is particularly important for marketing and ops teams who frequently repurpose content from multiple sources.

Use .text() for user or external content whenever possible.
Prefer element construction via the API for predictable DOM shape.
If HTML must be allowed, parse and sanitise before insertion.
Avoid mixing data and markup in concatenated strings.

Useful example: a team building a “related articles” widget from titles and URLs should create an anchor element, set the href attribute, and set the visible label using text insertion. This avoids the common mistake where a title like “<img onerror=…>” becomes executable content when injected as HTML.

Removing elements without leaking handlers.

Removing UI components is not just a visual change. If code attaches events to elements, those handlers can remain in memory even after the element is gone, depending on how they were bound and what references remain. Over time, particularly in single-page-like experiences (filters, modals, dynamic lists), this can create memory leaks and behaviour that looks “haunted”, such as clicks firing multiple times.

With jQuery, .remove() deletes elements from the DOM and cleans up associated jQuery data and event handlers. For many real-world sites, it is the safest default because it reduces the chance of leaving behind orphaned handlers. This is particularly relevant when components are repeatedly created and destroyed, such as toast notifications, dynamically inserted banners, or expandable FAQ items.

There are cases where removal is temporary and state should be preserved. jQuery’s .detach() removes an element from the DOM but keeps data and events. This is useful when a component must be moved elsewhere, re-ordered, or temporarily stored while another view is shown. It is also useful for performance, because rebuilding complex widgets from scratch can be slower than detaching and reinserting.

A third method, .empty(), clears a container’s children while leaving the container in place. This is useful for re-rendering a list within a stable wrapper, where the wrapper itself holds layout, styling, or event delegation. In systems that rely on delegated events (binding a click handler to a parent container), emptying and refilling children can be a clean pattern because the handler remains attached to the parent, not each child.

Use .remove() when the element is truly gone for good.
Use .detach() when the element is coming back and should keep state.
Use .empty() to refresh children but preserve the parent container.
Prefer event delegation for lists that change frequently.

Edge case to watch: if handlers are bound to global objects (window, document) and reference removed nodes via closures, memory can still leak. Cleaning up those listeners explicitly during teardown prevents slow degradation in long-running sessions, which matters for internal dashboards, client portals, and no-code admin tools where staff leave tabs open for hours.

State management with predictable classes.

UI state becomes messy when different parts of the code “kind of” track it in different ways. One function toggles inline styles, another sets an attribute, a third swaps text labels, and suddenly the page has contradictory signals. A stable approach uses CSS classes as the source of truth for visual state, with JavaScript responsible for changing classes and CSS responsible for appearance.

This pattern fits jQuery well. A component can gain an “active” state, “is-loading” state, or “has-error” state simply by adding or removing classes. The DOM stays readable, styling rules stay centralised, and debugging becomes simpler because a developer can inspect the element and immediately see its current state. It also aligns well with accessibility improvements, because state changes can be paired with aria attributes in the same place where the class is toggled.

jQuery’s .toggleClass() helps where state flips frequently, such as opening and closing a modal, expanding a navigation panel, or switching between monthly and annual pricing. Rather than writing two branches repeatedly, toggleClass encapsulates the intent: invert state.

For more complex behaviour, classes can be combined with data attributes, but class naming discipline matters. Teams often benefit from a small naming convention such as:

is-* for transient state (is-open, is-loading)
has-* for content conditions (has-results, has-error)
js-* for hook-only classes used by scripts (js-modal)

This keeps styling classes and scripting hooks from colliding. It also avoids the trap where a marketing change modifies a class name for styling reasons and accidentally breaks the JavaScript. In Squarespace environments, where designers frequently adjust classes in Code Blocks or custom CSS, separating “js hooks” from “visual classes” prevents brittle behaviour.

Practical example: a modal can be controlled by toggling a “is-visible” class on the modal wrapper and locking body scroll with a “is-locked” class on the body. CSS handles opacity, transform, and pointer-events. JavaScript only changes classes and sets focus. This produces cleaner code and a more consistent experience, especially across devices.

Preventing re-initialisation and event duplication.

As websites grow, initialisation code often ends up running more than once. This happens when scripts are loaded twice, when partial page updates re-run the same setup, or when a component is re-rendered without a proper teardown. The symptoms are subtle at first: click handlers firing twice, animations stuttering, or network requests multiplying.

A simple prevention method is to track a flag that marks whether a component has already been initialised. That flag can live in a module scope variable, or on the element itself using a data attribute. Once initialised, the code exits early on subsequent calls. This makes behaviour idempotent: running setup again does not change the outcome.

Another prevention pattern is binding events in a way that avoids duplicates. jQuery supports namespaced events, enabling unbinding of a specific handler group before rebinding. This is useful when a component must re-init due to dynamic content, but it should never accumulate multiple handlers. Teams can also use .one() for one-time initialisation triggered by a first interaction, such as lazy-loading a heavy widget when the user opens it the first time.

Encapsulating logic in closures and avoiding global variables reduces collisions across scripts, particularly on sites where multiple vendors inject their own JavaScript. This becomes increasingly relevant for SMB stacks where tracking scripts, chat widgets, scheduling embeds, and A/B testing tools all coexist.

Make initialisation idempotent using flags or element data markers.
Use event namespaces and unbind before rebinding when necessary.
Use .one() for “first-use” initialisation triggers.
Separate setup and teardown for components that re-render.

Operationally, this discipline prevents the “it gets slower over the day” problem. In real businesses, that translates into fewer support issues, less time debugging intermittent UI glitches, and more confidence when shipping incremental improvements.

These DOM management habits also pair well with broader content and support strategies. For instance, when a site embeds assistance layers or searchable help components, keeping initialisation clean and avoiding event duplication ensures those tools remain fast and reliable, which reduces friction across the customer journey.

Next, the same performance mindset can be extended beyond DOM manipulation into event handling patterns, asynchronous loading, and the measurement practices that reveal where real bottlenecks sit in production.

Play section audio

Basic effects and responsible animation.

Use effects when they support a task.

Animations can improve how a website feels by providing immediate feedback, signalling cause and effect, and helping users understand what just happened after a click, tap, or form submission. That said, effects are often non-essential, meaning the site can still function perfectly without them. The deciding factor is whether an animation actively reduces confusion, speeds up decision-making, or prevents mistakes. If the answer is “it only looks nice”, the effect may still be valid, but it should be treated as a design choice with a measurable cost in complexity, performance, and accessibility risk.

A common trap is using movement to compensate for unclear layout or weak hierarchy. When labels, spacing, and affordances are well-designed, the interface usually needs fewer moving parts. A simple state change, such as a button shifting colour on hover or a form field highlighting on error, can communicate status just as well as a complex sequence. Over-animating can create a cluttered UI where everything competes for attention, and that competition often pulls focus away from what matters: content, decision points, and completion of the primary user journey.

In practical terms, the best animations tend to be the ones users barely notice. A subtle transition on a filter panel that slides open can indicate “a new set of options is available”. A short fade on a success message can confirm “the action worked”. Even these small touches should map to an intent: confirmation, orientation, progress, or emphasis. Anything that cannot be tied to one of those intents should be treated as optional polish, and optional polish is the first thing to remove when performance or clarity is at risk.

When teams reach for JavaScript libraries, the temptation is to use what is available because it is easy. Libraries like jQuery historically made animation approachable, offering many effects and helper methods. Yet availability is not a reason to animate. A “menu bounce” might feel playful, but it can also introduce visual noise every time a user navigates. A modal that swoops in dramatically may feel premium, but it can slow down the flow for repeat users who just want to complete a task and leave.

Context matters. An e-commerce flow may benefit from calm, informative motion that supports purchase confidence, such as drawing attention to a “free returns” note when a user opens delivery details, or providing a gentle progress indicator in checkout. In contrast, a news or documentation site often prioritises scanning, reading speed, and low cognitive load, making movement more likely to irritate than to help. The “right” animation is rarely universal; it depends on audience expectations, device constraints, and the pace at which users want to move.

Brand alignment matters too, but brand should not override usability. A playful brand might use more expressive motion, while a corporate brand might stay restrained. Either can still be usable if animations remain predictable and do not block interaction. Cultural interpretation also plays a role: motion that suggests urgency, warning, or celebration in one market might read differently elsewhere. The safest strategy is to use motion to explain interface behaviour, not to communicate meaning that could be misunderstood.

Where animations truly earn their keep is in complex workflows. Multi-step forms, configuration flows, and onboarding sequences can be intimidating when they appear as a wall of fields. Carefully timed transitions can show “step completed”, “next step unlocked”, or “this section depends on your previous choice”. For example, revealing conditional fields with a short transition can help users understand that their selection directly changed what the system needs from them. This reduces perceived complexity and can lower abandonment rates, provided the movement is brief and consistent.

The main risk is cognitive overload. Too many moving elements demand attention, and attention is limited. When movement is constant, users stop trusting it as a signal and begin ignoring it, which defeats the purpose. Even worse, motion can mask important information if it delays visibility of critical content or creates uncertainty about whether the site is ready for interaction. Animation should support comprehension, not compete with it.

From here, the discussion naturally turns from “should it move” to “can everyone use it safely”, because accessibility is where most animation decisions become either professional or careless.

Avoid motion that harms accessibility.

Animation choices can exclude people. Users with vestibular disorders, migraine sensitivity, or certain neurodivergent profiles may experience discomfort, nausea, or disorientation when faced with intense motion, parallax scrolling, or rapid flashing. That makes accessibility a core design constraint, not a “nice to have” checkbox. Responsible teams treat motion as an opt-in enhancement rather than a mandatory experience.

Reducing harm starts with avoiding known triggers: large elements that move across the screen, constant background animation, fast zoom effects, and anything that flashes or strobes. Even when an animation feels subtle to the designer on a large monitor, it can feel aggressive on a mobile screen held close to the face, especially when a user is scrolling rapidly or dealing with glare. A safe baseline is to keep motion small, local, and tied to direct user interaction, rather than automated movement that runs without input.

A practical implementation pattern is to respect operating-system preferences for reduced motion. CSS supports this via the prefers-reduced-motion media query, which allows a site to swap animated transitions for instant state changes when the user has explicitly asked for less motion. This is not only considerate, it is increasingly expected across modern products. When reduced motion is enabled, teams can preserve meaning by keeping the same UI states while removing the travel, bounce, or fade that causes discomfort.

Equally important is offering predictable behaviour. Users with cognitive impairments often benefit from consistency: a panel should always open the same way, error messaging should always appear in the same location, and dismiss actions should behave reliably. If an animation is used, it should never hide where something went. For example, sliding a notification away is acceptable if it is obvious that it has been dismissed; teleporting it with a flashy effect can create confusion about whether the message was saved, sent, or deleted.

Testing should include real accessibility scenarios, not just automated checks. Teams can validate motion decisions by observing users with varied needs and by reviewing relevant guidance such as WCAG. Automated tools rarely flag motion that is “technically valid but practically uncomfortable”. User feedback fills that gap and often highlights edge cases, such as motion that is fine in isolation but becomes exhausting when repeated throughout a browsing session.

Timing is also part of accessibility. Long animations can increase discomfort because they prolong exposure, while ultra-fast animations can be hard to follow for users who need more processing time. The goal is not to pick one perfect duration for everyone, but to keep motion brief, give users control, and ensure that state changes remain comprehensible even when motion is removed entirely.

Once accessibility is addressed, the next constraint is performance. An animation that looks smooth on a high-end laptop can still be a poor choice if it causes lag on mid-range phones or drains battery during browsing.

Keep animation subtle and fast.

Subtle motion tends to be more effective because it supports interaction without becoming the main event. Teams can treat motion as part of the interface’s “micro-feedback layer”: it confirms actions, indicates continuity, and reduces the perceived harshness of sudden changes. When animation becomes theatrical, it often slows users down and can make a site feel less professional, even if the visuals are impressive.

Performance should be measured, not assumed. Resource-heavy effects can increase page weight, trigger extra layout work, and introduce jank, particularly on mobile devices where CPU and GPU resources are limited. This matters for founders and SMB teams because performance affects conversion, SEO, and perceived trust. If a checkout step stutters, users interpret that as instability. If a services site feels sluggish, prospects question professionalism.

For quick wins, simple fades are often enough. In JavaScript-driven interfaces, methods such as fadeIn() and fadeOut() can create gentle transitions without requiring elaborate choreography. Still, the presence of a convenient method should not become the justification for adding motion. Each effect should be attached to a user outcome, such as “reduce mis-clicks by clearly showing the menu has opened” or “help users notice a validation message”.

Duration and easing heavily influence perceived quality. Many interaction animations work best when they feel almost instant. A common guideline is to keep micro-interactions under about 300 milliseconds, because users perceive that as responsive. Longer animations are better reserved for deliberate transitions, such as moving between major sections of an app-like experience. Easing functions also matter: linear movement feels mechanical, while eased transitions can feel natural and reduce visual harshness, especially in UI elements that expand or collapse.

Loading and processing indicators deserve special attention. When a site needs time, users should see clear feedback, but that feedback should be lightweight. A simple spinner or progress bar communicates “work is happening” without wasting CPU cycles on complex animation. In data-heavy experiences, such as dashboards built on Knack or automation-driven flows connected through Make.com, even small performance regressions can compound. Lightweight feedback helps keep the interface stable while background tasks run.

Mobile battery impact is a practical constraint that often gets ignored. Continuous animations, looping effects, or multiple simultaneous transitions can keep the GPU active and drain battery faster. While individual users may not attribute battery drain to one site, the outcome is still negative behaviour: they leave earlier, engage less, and return less frequently. Keeping effects minimal and event-driven helps reduce that hidden cost.

With subtlety and performance in place, the next decision is choosing the right tool for the job. For many everyday interactions, CSS can outperform JavaScript-based animation approaches and reduce maintenance overhead.

Prefer CSS transitions for basics.

For straightforward interactions such as hover states, focus states, small fades, and simple transforms, CSS transitions are often the cleanest approach. They run closer to the browser’s rendering engine, generally require less code, and reduce JavaScript dependency. The outcome is typically smoother motion and fewer opportunities for scripts to conflict with other parts of a site, particularly on platforms where multiple embeds and third-party scripts are present.

CSS is also easier to maintain. A team can adjust timing, easing, and property changes in a single stylesheet instead of rewriting logic in event handlers. This is useful in fast iteration cycles, where a marketing lead might request a tweak to interaction feel, or a product manager might want to reduce motion after reviewing user recordings. When motion is defined in CSS, these adjustments become more accessible and less risky.

There is also a reliability advantage. JavaScript-driven animation can be interrupted by main-thread work, such as heavy scripts, analytics beacons, or complex DOM updates. CSS transitions can still be affected by poor performance, but they avoid some of the failure modes that come from competing JavaScript tasks. For Squarespace sites in particular, where templates and third-party scripts are common, keeping simple motion in CSS can reduce the chance of unexpected side effects.

CSS transitions can also be combined with transforms to create polished effects without heavy cost. For example, transitioning opacity and transform together can create a clean “fade and lift” interaction for cards or buttons. The key is restraint: the motion should remain short, consistent across the site, and tied to interaction. When the same pattern is repeated, users learn it quickly, which improves perceived usability and makes the interface feel cohesive.

From an accessibility standpoint, CSS also pairs nicely with reduced-motion preferences. It is straightforward to define a default animation and then override it to “none” or a near-instant transition when reduced motion is detected. This keeps the interface consistent while respecting user settings.

Once the implementation approach is chosen, teams still need to validate that real devices deliver the intended experience. Desktop testing is not enough, because mobile constraints can change everything from frame rate to perceived timing.

Test on mobile and low power.

Mobile performance is where animation decisions become real. A desktop machine can hide inefficient implementation, while mid-range phones quickly reveal frame drops, delayed input response, and scroll stutter. Testing on mobile should be treated as part of quality assurance, not an optional final pass. The goal is to verify that effects do not interfere with touch interactions, do not block content, and do not introduce noticeable delays in navigation.

Tools such as Chrome DevTools can simulate slower CPUs, reduced network conditions, and mobile viewports. This helps teams spot bottlenecks early, such as animations that trigger layout thrashing, excessive repainting, or heavy script execution. In practice, throttling often reveals that an effect which felt “smooth” on a developer machine becomes jittery on a phone, which is exactly when users start mistrusting the site.

Real-device testing remains essential, because simulation cannot perfectly mimic GPU behaviour, thermal throttling, and browser quirks. A useful approach is to maintain a small device matrix that reflects the audience: at least one older iPhone, one mid-range Android device, and a modern flagship device. If a business serves global markets, testing on budget devices is especially important, because those devices are common in many regions and are more likely to expose performance issues.

Teams can also validate motion decisions by checking analytics and behaviour signals. If an animated element correlates with higher bounce or lower completion, the animation might be adding friction. Session recordings and heatmaps can show whether users hesitate during animated transitions or repeatedly tap because they think the interface is unresponsive. These signals are more actionable than subjective opinions about whether something “looks good”.

Finally, user feedback should influence iteration. People will rarely say “the animation is heavy”, but they will say “the site feels slow” or “it’s annoying”. That feedback can be translated into concrete actions: reduce duration, remove loops, replace a complex effect with a simple state change, or move an interaction from JavaScript to CSS.

With a mobile-tested and accessible motion system in place, the next step is to define a consistent motion style guide so effects remain coherent across new pages, campaigns, and future feature additions.

Play section audio

Conclusion and next steps.

jQuery still fits certain jobs.

Even with modern frameworks dominating new builds, jQuery continues to make sense in narrowly defined scenarios. Its core value has always been speed to implementation: a small set of readable helpers that reduce the friction of common front-end tasks. As of 2025, nearly 195 million websites still use it, which signals not “trendiness” but inertia, compatibility, and the reality of long-lived websites that are updated incrementally rather than rebuilt from scratch. In practical terms, jQuery tends to appear where a team needs quick interface behaviour, a small interactive enhancement, or an expedient patch inside an older codebase that already depends on it.

For founders and SMB teams, the decision is less ideological and more operational. If a marketing site needs a light interaction, such as a simple accordion, a class toggle, a form hint, or a one-off animation, jQuery can be a pragmatic choice when it avoids a heavier toolchain. That said, its usefulness increases when the change must be delivered quickly, the risk of altering an existing stack is high, or the organisation lacks the appetite to introduce build steps, components, and a framework-specific maintenance burden for a small UI win.

Strengths and limitations need clarity.

To use jQuery effectively, teams should understand what it is excellent at, and what it was never designed to solve. Historically, one major benefit was cross-browser compatibility. jQuery smoothed over differences in how browsers implemented event handling, element selection, and AJAX. That mattered when browser support was inconsistent and front-end code regularly broke across environments. Many of those gaps have narrowed, so the “write once, run everywhere” advantage is less decisive for modern browsers than it was a decade ago.

Its other clear strengths remain practical. The API is straightforward for selecting elements, responding to clicks and key events, and chaining multiple UI operations in a compact, readable way. It also has a deep ecosystem of plugins and examples, which can still be useful when a legacy plugin is already embedded in a workflow and replacing it would introduce regression risk. Documentation and community answers are plentiful, which helps less specialised teams ship small improvements without extended ramp-up time.

Limitations surface when teams attempt to stretch jQuery into a role it does not naturally fill. It does not provide application structure, state management, routing, or robust patterns for complex, long-lived user interfaces. jQuery-centric code can become difficult to maintain when it grows into many scattered event handlers, implicit dependencies, and “DOM-as-state” assumptions. In performance terms, it is not automatically slow, but it can encourage patterns that are inefficient on modern, interactive pages, such as repeated DOM queries in loops, frequent layout thrashing, or attaching too many handlers to many nodes. This is where clear engineering discipline matters more than the library itself.

Choose tools based on the work, not fashion.

Modern alternatives suit new builds.

For new projects, modern frameworks usually provide a more robust base because they formalise how the interface is composed, updated, and tested. Tools such as React, Angular, and Vue encourage a component model where UI is broken into reusable pieces, interactions are represented through predictable state, and changes are easier to reason about over time. This becomes especially important when an application grows beyond a handful of interactions and starts to behave like a product: user accounts, dashboards, filtering, saved settings, subscription flows, and cross-page experiences.

These frameworks also shape team workflows. They integrate well with tooling for linting, automated testing, type checking, bundling, and performance optimisation. That ecosystem can raise code quality and reduce production surprises, but it also adds overhead: build pipelines, dependencies, and a need for someone to own the front-end architecture. For SMBs, the best alternative is not always “the most powerful” framework, but the one that fits the team’s capacity to maintain it. A lightweight stack that is well understood will outperform a sophisticated stack that becomes neglected.

There is also a middle path that many teams overlook: using modern browser APIs directly. Native DOM selection, event listeners, class toggling, and the Fetch API often cover the same ground jQuery once dominated, without an additional dependency. When the goal is a few enhancements on a content-led site, native JavaScript can be the cleanest long-term approach, as long as the team documents patterns and avoids ad-hoc scripts sprinkled across templates.

Legacy support and prototyping remain valid.

jQuery is still a strong option when the goal is maintaining or extending an existing system. Legacy environments often contain older plugins, older patterns, or CMS templates that were built around jQuery assumptions. In those cases, removing jQuery can cost more than keeping it, because the true cost is regression testing, QA time, and the risk of subtle behavioural differences. Teams can treat jQuery as a compatibility layer: keep it where it is, isolate new code, and gradually refactor only when there is a clear business reason.

Rapid prototyping is another reasonable use. When an operator or marketer needs to validate a concept, such as a new landing page interaction, a lightweight UI tweak, or a proof-of-concept flow, jQuery can reduce time-to-first-result. The key is to label prototypes honestly. If the prototype becomes production, the team should decide whether to harden the jQuery implementation with better structure, tests, and performance checks, or rebuild the feature in a more scalable approach.

There are also edge cases where jQuery remains the least risky choice even on “modern” sites. Examples include integrating a mature third-party widget that depends on jQuery, operating inside a constrained environment where bundlers are unavailable, or adding behaviour into legacy CMS fragments where the development pipeline is not accessible. In these situations, the best practice is to keep the jQuery surface area small: one file, clear naming, minimal global variables, and explicit teardown when components are removed or pages change.

Track standards, performance, and security.

The web platform changes quickly, so teams benefit from periodically reassessing their assumptions. Modern browsers regularly ship improvements that replace older library-driven patterns, including better selectors, richer form validation, more consistent event behaviour, and stronger accessibility primitives. By watching browser release notes and reputable engineering blogs, teams can identify when a legacy pattern is now natively supported and simpler to maintain without extra abstractions.

Performance and user experience should be treated as measurable, not guessed. Tools such as Lighthouse can highlight slow scripts, render-blocking assets, and interaction delays that disproportionately affect mobile users. jQuery itself is rarely the only culprit; the bigger risks are patterns like heavy plugins, large bundles, unnecessary animations, and unoptimised images. A sensible workflow is to benchmark before and after changes, then make targeted adjustments such as debouncing scroll handlers, caching DOM selections, reducing reflows, and deferring non-critical scripts.

Security discipline matters just as much. Keeping dependencies current reduces exposure to known vulnerabilities, and this applies to jQuery and any plugin built on top of it. The highest-risk area tends to be third-party plugins and snippets copied from unknown sources, especially when they manipulate HTML strings, inject untrusted content, or rely on outdated versions. Teams should vet plugins, pin versions, and remove abandoned dependencies where possible. If the site accepts user input, strict validation and output escaping are essential regardless of the front-end library.

Make the decision repeatable.

A useful next step is turning “Should they use jQuery?” into a checklist that a team can apply consistently. If a site is primarily content-led and needs a few enhancements, native JavaScript or a small, well-contained jQuery script may be sufficient. If the site is evolving into an application with complex UI state, a component framework becomes a more stable foundation. If the organisation is maintaining a long-lived legacy system, the safest path may be to keep jQuery and modernise in layers.

Scope: Is the work a few interactions or a full application UI?
Existing stack: Does the current codebase already depend on jQuery or jQuery plugins?
Team capacity: Can the team maintain a framework, tooling, and upgrades over time?
Performance targets: Are there clear metrics for load time and responsiveness, especially on mobile?
Risk tolerance: Would removing jQuery introduce hard-to-test behavioural changes?

From here, the most effective move is to audit the current front end, identify where jQuery is used, and categorise each usage as “keep”, “replace with native”, or “replace with framework”. That creates a realistic modernisation plan that respects delivery speed, reduces unnecessary rewrites, and helps teams invest engineering time where it produces the biggest operational and customer impact.

Frequently Asked Questions.

What is jQuery?

jQuery is a lightweight JavaScript library that simplifies HTML document traversing, event handling, and AJAX interactions for rapid web development.

Why was jQuery created?

jQuery was created to address inconsistencies in how different browsers handle JavaScript, providing a unified API for developers.

When should I avoid using jQuery?

Avoid using jQuery when modern native APIs can accomplish the same tasks more efficiently, especially for performance-critical applications.

Is jQuery still relevant today?

Yes, jQuery remains relevant for maintaining legacy projects and for quick prototyping, although modern frameworks are often preferred for new projects.

What are some common tasks jQuery simplifies?

jQuery simplifies tasks such as selecting DOM elements, handling events, and making AJAX requests with less code.

How does jQuery handle cross-browser compatibility?

jQuery abstracts browser differences, allowing developers to write code that works uniformly across all major browsers.

Can jQuery be used with modern frameworks?

Yes, jQuery can be used alongside modern frameworks, but care should be taken to avoid conflicts and maintain code clarity.

What are the performance considerations when using jQuery?

Performance considerations include avoiding unnecessary DOM manipulations and testing animations on mobile devices to ensure smooth user experiences.

How can I learn more about jQuery?

Developers can learn more about jQuery through its extensive documentation, online tutorials, and community forums.

What are some popular jQuery plugins?

Popular jQuery plugins include jQuery UI for user interface interactions, DataTables for enhancing tables, and Lightbox for displaying images.

References

Thank you for taking the time to read this lecture. Hopefully, this has provided you with insight to assist your career or business.

Lask, S. (2025, November 5). jQuery will outlive half of today’s JavaScript frameworks - here's why. DEV Community. https://dev.to/sylwia-lask/jquery-will-outlive-half-of-todays-javascript-frameworks-heres-why-2mmd
Alfy. (2025, October 4). How functional programming shaped (and twisted) frontend development. Alfy Blog. https://alfy.blog/2025/10/04/how-functional-programming-shaped-modern-frontend.html
LogRocket. (2019, August 13). The history and legacy of jQuery. LogRocket Blog. https://blog.logrocket.com/the-history-and-legacy-of-jquery/
Jones, A. (2024, July 26). The evolution of JavaScript: A journey from jQuery to modern frameworks: 2012 — present (part 1). Medium. https://medium.com/@ajonesb/the-evolution-of-javascript-a-journey-from-jquery-to-modern-frameworks-2012-present-1b0536f7273b
Docker. (2025, October 17). Why I still use jQuery in 2025 (and when not to). Docker. https://www.docker.com/blog/why-i-still-use-jquery-2025/
Code Institute. (2022, January 21). All About jQuery: What It Is and How It Enhances Web Development. Code Institute. https://codeinstitute.net/global/blog/what-is-jquery/
Mozilla Developer Network. (n.d.). Client-side storage. MDN Web Docs. https://developer.mozilla.org/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Client-side_storage
Alibaba Cloud. (n.d.). An introduction to jQuery. Alibaba Cloud. https://www.alibabacloud.com/blog/an-introduction-to-jquery_595778
Universidad de Cantabria. (n.d.). jQuery and Ajax Tutorial. personales.unican.es. https://personales.unican.es/corcuerp/ingweb/notes/jQuery_Basics.html
Savvy. (2024, October 15). Animating elements with jQuery: A step-by-step tutorial. Savvy. https://savvy.co.il/en/blog/complete-javascript-guide/jquery-animate-elements-tutorial/

Key components mentioned

This lecture referenced a range of named technologies, systems, standards bodies, and platforms that collectively map how modern web experiences are built, delivered, measured, and governed. The list below is included as a transparency index of the specific items mentioned.

ProjektID solutions and learning: