What is jQuery? Learn the most popular JavaScript library

Despite the rise of modern frameworks like React and Vue, jQuery remains a vital tool for legacy projects and platforms like WordPress. Its simplicity and versatility make it a go-to choice for quick development tasks.

Curious to see it in action?

This blog will introduce you to jQuery, guide you on how to get started, and help you write cleaner, more efficient code. By the end, you might wonder how you ever coded without it!

What is jQuery?#

jQuery is a lightweight, fast, and open-source JavaScript library designed to simplify HTML document traversal, event handling, animations, and AJAX interactions. With its intuitive syntax and powerful functionality, jQuery makes it easier for developers to create interactive web applications without writing lengthy, complex JavaScript code.

jQuery is one of the most popular JavaScript libraries in the world, used by over 70 million websites—including major tech giants like Netflix, Google, IBM, and Microsoft.

The core philosophy of jQuery is embodied in its tagline:

“Write less, do more.”

This means that developers can accomplish the same task using just one or two lines of jQuery instead of writing multiple lines of vanilla JavaScript.

Key features of jQuery#

jQuery simplifies various aspects of front-end development. Some of its most powerful features include:

• Event handling: Easily manage user interactions like clicks, mouse movements, and keyboard input.

• DOM manipulation: Seamlessly select, modify, and update elements in the HTML document.

• Animations and effects: Implement smooth animations, transitions, and effects with minimal code.

• AJAX support: Load content dynamically without refreshing the page, improving user experience.

• Cross-browser compatibility: Ensure consistent behavior across all major browsers.

With these capabilities, jQuery remains a valuable tool for both beginners and experienced developers.

Why learn jQuery?#

Although modern frameworks like React, Vue, and Angular have gained popularity, jQuery remains relevant, particularly in legacy codebases, CMS platforms like WordPress, and frameworks like Bootstrap. Understanding jQuery is still beneficial for several reasons:

Simplicity and readability#

• jQuery reduces complex JavaScript operations to short, readable statements.

• It provides pre-built functions for common tasks like AJAX requests, form validation, and element selection.

Widely used in enterprise projects#

• Many large companies still rely on jQuery in existing projects.

• CMS platforms like WordPress and Magento use jQuery extensively.

Excellent for beginners#

• jQuery serves as a great first step into the world of JavaScript development.

• It offers easy-to-learn syntax, making it ideal for junior developers.

Compatibility with other libraries#

• Many JavaScript libraries and plugins depend on jQuery.

• Even if a project uses modern frameworks like React, jQuery can still be helpful for quick prototyping.

Explore Educative’s comprehensive course if you’re eager to dive deeper into jQuery and enhance your skills! It’s packed with hands-on exercises, real-world projects, and expert insights to help you master jQuery efficiently.

Let's compare Vanilla JavaScript and jQuery and see which one is better.

jQuery vs. vanilla JavaScript: Which one is more efficient?#

To fully understand the power of jQuery, let’s compare a simple DOM manipulation task using both vanilla JavaScript and jQuery. We’ll analyze their differences in terms of code length, readability, and execution efficiency.

Vanilla JavaScript approach#

In vanilla JavaScript, we need to follow multiple steps to select an element, create new nodes, set their properties, and attach them to the DOM.

Breaking down the steps:

1. Wait for the DOM to load before executing the script.

2. Select the parent container where the new elements will be added.

3. Loop through five times, creating a new <p> element on each iteration.

4. Set the text content of the newly created element dynamically.

5. Assign a CSS class for styling purposes.

6. Append each new paragraph to the selected parent container.

While this approach works perfectly, it requires multiple lines of code to achieve a relatively simple operation.

jQuery approach#

With jQuery, the same operation is drastically simplified into a few concise lines of code.

Why is this code more efficient?

• Shorter and cleaner syntax: The .append() method directly injects HTML content, eliminating the need for document.createElement() and appendChild().

• Automatic DOM ready handling: The $(document).ready() function ensures the script executes only after the DOM is fully loaded, preventing errors.

• More readable and intuitive: jQuery makes it easy to understand what’s happening at a glance.

Understanding jQuery syntax#

The jQuery library is built around selectors, event handlers, and DOM traversal methods.

The three key components of jQuery syntax are:

1. $() or jQuery(): The core function that wraps elements in jQuery methods

2. Selector: Selects HTML elements (similar to CSS selectors).

3. Action: Defines what happens to the selected elements (e.g., animations, events).

Basic jQuery syntax#

• The $() function selects an element.

• The action() method performs an operation on the selected element.

Example

We can take an example of hiding the button. The following jQuery code hides an element when a button is clicked:

Let’s have a look at what’s happening here:

• When the button with id="hideButton" is clicked, the #content element disappears immediately.

• .hide() removes the element from view without deleting it from the DOM.

However, this hides the element abruptly, which isn’t ideal for user experience. Instead, we can use smooth transitions.

DOM and jQuery’s role in DOM manipulation#

The Document Object Model (DOM) is a hierarchical representation of an HTML document. It acts as an interface between HTML and JavaScript, enabling developers to dynamically manipulate web page elements.

jQuery provides powerful methods for selecting, modifying, traversing, and animating DOM elements with minimal code.

jQuery DOM manipulation examples#

Using jQuery, developers can:

• Easily select elements using CSS-like selectors.

• Modify HTML content dynamically (e.g., adding or removing elements).

• Change attributes and styles of elements effortlessly.

• Handle user interactions and events (clicks, hovers, form submissions).

• Create smooth animations without CSS or third-party libraries.

Example

The following jQuery script selects all <p> elements and changes their text color to blue:

jQuery selectors: Finding elements efficiently#

One of the most powerful features of jQuery is its ability to select and manipulate HTML elements efficiently. Just like CSS selectors, jQuery provides a variety of methods to target elements dynamically.

With jQuery selectors, you can:

• Select single or multiple elements using various rules.

• Apply changes dynamically (e.g., modify text, add styles, animate elements).

• Filter and refine selections using advanced selectors.

• Efficiently traverse the DOM to manipulate child or sibling elements.

How jQuery selectors work#

The basic syntax for jQuery selectors follows this pattern:

Breaking it down:

• $(): The jQuery function that wraps the selector.

• Selector: The target element to be manipulated.

• Action: The method or operation performed on the selected element.

Example

Changing the background color of all <p> elements

Common jQuery selectors#

jQuery selectors are categorized into five main types:

Handling events in jQuery: Making pages interactive#

jQuery simplifies event handling by using the .on() method. This ensures smooth user interactions with buttons, input fields, and more.

Let’s take an example of handling click events:

Explanation:

• $("#clickButton").click(function() {...}) attaches a click event listener to an element with id="clickButton".

• When clicked, it triggers an alert("Button Clicked!").

Smooth transition effect (Hiding and showing elements)#

To enhance user experience, smooth transitions can be used instead of sudden element disappearance.

How to install jQuery in your project#

To use jQuery, you can include it in your project using one of three methods:

1. Include via CDN (Recommended)

This is the quickest way to use jQuery without downloading files.

2. Download and use locally

If you prefer to host jQuery on your own server, download it from jQuery’s official website.

3. Install via npm or yarn (For Node.js/Modern apps)

Your first jQuery project#

Let’s build a basic interactive to-do list application using jQuery.

Project goals#

• Add new tasks dynamically when the “Add Task” button is clicked.

• Validate the input field (Show an error if empty).

• Display an alert confirming the new task.

• Clear the input field after task submission.

In the playground below, you can test your understanding.

If you get stuck, click the “Show Solution” button.

We’re confident you’ve put great effort into this project! Now, let’s break down the solution step by step, analyzing each line to fully understand how it works and why it’s implemented this way. By doing this, you’ll gain a deeper insight into jQuery’s functionality, event handling, and DOM manipulation. Let’s dive in!

• Line 3: We retrieve the value from the input field (#taskInput) using .val().

• Lines 5–6: We check if the input field is empty after trimming whitespace and display an alert message if the user tries to add a blank task.

• Line 8: We create a new <li> element containing the task text and add it dynamically to the <ul id="taskList"> using .append().

• Line 9: We display a confirmation message showing the added task.

• Line 10: We reset the input field to an empty string after adding a task.

Wrapping up and next steps#

jQuery remains one of the most efficient and user-friendly JavaScript libraries for DOM manipulation, event handling, animations, and AJAX interactions. It simplifies complex JavaScript tasks, reducing long, verbose code into a few concise lines. Whether you’re working on a legacy project, a CMS like WordPress, or just getting started with JavaScript, understanding jQuery will enhance your development skills and boost your productivity.

By now, you’ve learned how jQuery streamlines event handling, dynamic content updates, and user interactions. As you continue exploring, try experimenting with more animations, AJAX requests, and advanced event delegation to unlock jQuery’s potential fully.

To expand your JavaScript expertise, explore these related blogs:

• JavaScript developer roadmap

• JavaScript tutorial: Get started with Canvas animations

• PHP vs. JavaScript: Comparison and applications

• TypeScript vs. JavaScript: What’s the difference?

Want to dive deeper into JavaScript? Check out Educative’s courses for a hands-on learning experience!