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JavaScript and jQuery: The Core Client-Side Web Technologies

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JavaScript and jQuery have revolutionized the way we build interactive, dynamic websites and web applications. Once a niche tool for adding minor flourishes to pages, JavaScript has grown into a robust programming language powering complex web apps. Meanwhile, the jQuery library has made JavaScript even more accessible and convenient for developers.

This article will provide a comprehensive introduction to JavaScript and jQuery. We’ll explore the origins and evolution of these technologies, their key capabilities, and how they work together to bring websites to life in the browser. Whether you’re new to web development or looking to level up your skills, understanding JavaScript and jQuery is essential.

JavaScript: The Native Language of Web Interactivity

JavaScript first appeared in 1995, and has gone through several evolutions since. But even from the beginning, its key purpose has been adding dynamic, interactive elements to web pages.

The Origins and Evolution of JavaScript

JavaScript was created at Netscape in 1995 by Brendan Eich. Netscape Navigator was the leading web browser at the time, and JavaScript was initially known as LiveScript.

The name was changed to JavaScript to capitalize on the popularity of Java programming language. However, JavaScript is quite distinct from Java, with a different syntax and uses.

Microsoft released their own implementation called JScript for Internet Explorer. Over time, JScript and JavaScript evolved with slight differences. But eventually the standardized ECMAScript specification united the languages.

Today, JavaScript powering interactivity on websites and complex web applications. All modern web browsers support JavaScript without any plugins needed. It has grown into one of the most widely used programming languages in the world.

How JavaScript Works on Web Pages

JavaScript code can be embedded directly on HTML pages within <script> tags. For example:

  alert('Hello World!');

The script tags contain JavaScript code that will execute in the browser as the page loads.

JavaScript can also be loaded from external .js files, which is preferred for larger scripts:

<script src="myscript.js"></script>

This separation keeps HTML markup clean and makes JavaScript reusable across pages.

JavaScript code triggers actions based on user interactions and events, like clicking buttons, scrolling, key presses, and more. It can manipulate page content, make API calls, animate elements, validate forms, and nearly everything else dynamic sites do.

Major Capabilities and Uses of JavaScript

Some of the most significant things JavaScript enables on the front-end include:

  • Dynamically Modifying HTML and CSS – JavaScript can create, add, edit, and remove HTML elements and CSS styles on the fly. This allows changing what users see as they interact with the page.
  • Responding to Events – Client-side event handlers like onclick and onscroll allow triggering code when users click, scroll, submit forms, and more.
  • Animating Elements – JavaScript powers transitions, animations, and motion formodern web UI. This includes CSS transforms and transitions.
  • Making AJAX Requests – The XMLHttpRequest API allows communicating with servers asynchronously for dynamic content updates without reloading pages.
  • Client-Side Form Validation – Scripts can check user input on forms before submitting to improve UX.
  • Drawing Graphics and Charts – Libraries like Canvas allow rendering 2D and 3D graphics programmatically in the browser.
  • WebGL 3D Graphics – For advanced 3D graphics and games, WebGL enables OpenGL-accelerated 3D and 2D graphics entirely in browser-native JavaScript.
  • App-Like Web Experiences – JavaScript powers full-featured web applications like Google Docs, Trello, Figma, and more.

This wide range of capabilities makes JavaScript the most essential language for front-end web development today. Nearly every interactive site leverages JavaScript.

Example JavaScript Uses on Websites

To see JavaScript in action, some examples include:

  • Drop-down Navigation Menus – Navigation bars that show/hide dropdown submenus on click.
  • Interactive Maps – Google Maps and services use JavaScript for interactive panning/zooming.
  • Form Validation – Checking email, password, phone, and other field formats before submitting a form.
  • Live Search/Filter – Updating search/filter results dynamically as user types.
  • Content Sliders/Carousels – Animating between panels of content, like home page hero sections.
  • Scroll Effects – Revealing animations and sticky elements that respond on scroll, like fixed headers.
  • SPA Navigation – Updating the browser URL and history without full page reloads for single page apps.

These are just a small sampling of JavaScript’s vast range of front-end applications. Nearly all non-trivial websites rely on JavaScript to create compelling user experiences.

jQuery is a JavaScript library, meaning it is a reusable set of helper functions written in JavaScript. Rather than a standalone language, it extends and simplifies working with JavaScript.

The jQuery library first released in 2006 and quickly became one of the most widely used tools in web development. Understanding jQuery is key for front-end programmers.

The History and Origins of jQuery

jQuery was created in 2006 by John Resig while working at Mozilla. The original motivation was to simplify and extend JavaScript capabilities for web developers.

Prior JavaScript libraries like Prototype, Dojo and MooTools already existed. But jQuery proved simpler and lighter than competitors while providing cross-browser normalization that was desperately needed at the time.

The concise $ selector and chainable syntax of jQuery immediately resonated with developers. Adoption exploded starting in 2007. Soon jQuery became the most used JavaScript library on the web.

Major sites like Google, Microsoft and Twitter used jQuery alongside their own custom frameworks. It helped propel the web from static to dynamic sites and fueled the client-side JavaScript revolution.

Why Use jQuery? Key Benefits Explained

jQuery rose to prominence because it elegantly solved several key problems in early JavaScript development:

  • Cross-Browser Normalization – Writing cross-browser compatible JavaScript was extremely challenging before jQuery. But jQuery provided unified APIs that worked consistently across different browsers.
  • Shorter, Simpler Syntax – jQuery uses CSS selector syntax for DOM queries and chaining to cut down on code compared to verbose native JavaScript.
  • Built-in AJAX – The $.ajax() method standardizes AJAX requests and provides useful callbacks and helpers without needing to use the native XMLHttpRequest object directly.
  • Animation Methods – jQuery includes powerful methods like fadeIn(), slideUp(), and animate() that make web animation simpler.
  • Event Handling – Methods like click(), hover(), on() and off() abstract away inconsistent native browser event systems into a unified API.
  • DOM Manipulation – jQuery makes common DOM operations like modifying classes, attributes, and CSS easier with methods like addClass() and css().
  • Cross-platform – jQuery works reliably across all major desktop and mobile browsers and environments.

The combined benefits enabled developers to write JavaScript faster with fewer hacks and inconsistencies between platforms. jQuery allowed focusing on functionality rather than worrying about cross-browser quirks.

Common Examples of jQuery Usage

Some examples that highlight how jQuery simplifies common JavaScript tasks:

DOM Querying

Vanilla JS:




Event Handling

Vanilla JS:

var btn = document.getElementById('myBtn');
btn.addEventListener('click', handleClick);




Vanilla JS:

var xhr = new XMLHttpRequest();'GET', '/data.json');
xhr.onload = function() {
  // ...


$.get('/data.json', function(data) {
  // ...  

This simplified syntax and cross-browser normalization enabled jQuery to completely change client-side web development.

The Partnership of jQuery and JavaScript

While jQuery revolutionized how we use JavaScript, it’s important to remember it is a library rather than a language. jQuery provides helper functions that utilize JavaScript underneath.

Understanding core JavaScript is still vital for any serious front-end developer. You will encounter both pure JavaScript and jQuery in projects today.

Advantages of Vanilla JavaScript (No Library)

While jQuery remains popular, vanilla JavaScript has improved enormously over the years. The need for jQuery’s cross-browser helpers has lessened.

Some benefits of using plain JavaScript include:

  • No Dependencies – Vanilla JS requires no libraries to load. jQuery adds about 85KB minified.
  • Performance – Modern browser APIs allow faster DOM queries and manipulation without overhead from jQuery function calls.
  • Spec Alignment – Vanilla JavaScript code aligns well with the current ES6+ specs for future-proofing.
  • Promises and Async – Native promises and async/await integrate well for async code compared to jQuery’s callback style.
  • No Conflicts – Eliminates possible conflicts between jQuery and other libraries on a project.
  • Module Support – Clean import/export syntax for modules works seamlessly in JavaScript. jQuery has no native module system.

So while jQuery still fills useful niches, vanilla JS often provides the best performance, alignment with standards, and interoperability with modern tools and modules.

Advantages of jQuery for Browser Support and Backwards Compatibility

However, jQuery retains benefits when legacy browser support and backwards compatibility are required:

  • IE 6-8 Support – jQuery works on old IE versions that lack modern JavaScript APIs.
  • Unified APIs – jQuery smooths over inconsistencies and missing APIs in dated browsers.
  • Mobile Support – jQuery provides a single codebase that works on a wide range of legacy mobile devices.
  • Cross-Platform Testing – Unit testing jQuery code avoids needing to run tests across many environments.
  • ** AJAX and Animation Fallbacks** – jQuery’s APIs fall back to older techniques when cutting edge ones aren’t supported.
  • Quick Prototyping – jQuery’s compact syntax remains excellent for rapid prototyping and proof-of-concept work.

So there are still strong cases to use jQuery when legacy browser support is required, or for quick prototyping where vanilla JS might be overkill.

Best Practices for Integration

Many projects use a combination of vanilla JS and jQuery today. Some tips for integrating them effectively:

  • Load jQuery from a CDN like Google’s or from npm when needed, instead of bundling it locally by default.
  • Scope jQuery use to just components that require it, rather than loading it globally.
  • Migrate any new components to use modern vanilla JS instead of jQuery.
  • Make use of jQuery’s noConflict() mode if it needs to coexist with other libraries.
  • Use JavaScript modules and bundlers like Webpack to include jQuery only in relevant components.

So while both remain relevant today, vanilla JavaScript should be preferred for optimal performance and alignment with modern standards when possible. jQuery fills in the gaps when legacy browser support or quick prototyping are needed.


JavaScript and jQuery helped transform static web pages into the dynamic, interactive experiences that dominate the web today. While other technologies like HTML and CSS handle markup and styling, JavaScript brings interfaces to life with dynamic behavior.JavaScript serves as the core programming language that powers interactivity across the modern web. Meanwhile, jQuery rose to popularity as a helper library that simplified cross-browser JavaScript development. It features chainable syntax and normalized APIs for DOM manipulation, AJAX, events, animation, and more.

While jQuery usage has declined in favor of modern vanilla JavaScript, it still fills important niches. jQuery is useful for legacy browser support or quick prototyping and proof-of-concept work.Understanding both pure JavaScript and jQuery is vital for professional front-end web developers today. Mastering these client-side technologies allows you to create compelling, responsive user experiences powered by scripting.

Nisha Kumari

Nisha Kumari

Nisha Kumari, a Founding Engineer at Bito, brings a comprehensive background in software engineering, specializing in Java/J2EE, PHP, HTML, CSS, JavaScript, and web development. Her career highlights include significant roles at Accenture, where she led end-to-end project deliveries and application maintenance, and at PubMatic, where she honed her skills in online advertising and optimization. Nisha's expertise spans across SAP HANA development, project management, and technical specification, making her a versatile and skilled contributor to the tech industry.

Written by developers for developers

This article was handcrafted with by the Bito team.

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