What is JQuery?

In web development, writing JavaScript can changes page content or reacts to user actions can be complex and redundant. jQuery exists to facilitate complex tasks in a faster and simpler way. This article will explain jQuery in a manner that will allow you to quickly understand how to utilize it for building interactive websites. You will learn how jQuery will allow you to select page elements, handle events, including clicks and form inputs, as well as make elements animate with smooth transitions and only minimal amounts of code.

Table of Contents:

• What is jQuery?
• Why Use jQuery in Modern Development?
• How to Include jQuery in Your Project
  • Using the jQuery CDN
  • Downloading and Hosting jQuery Locally
• Basic jQuery Syntax for Beginners
• Manipulating HTML and CSS with jQuery
  • Changing Content and Attributes
  • Adding and Removing Classes
• Handling Events in jQuery
• Limitations of jQuery
• Conclusion

What is jQuery?

jQuery is a fast, lightweight JavaScript library that makes working with HTML documents, managing animations, and event handling easier. John Resig initiated jQuery in 2006. jQuery changed the way we work with the web development process by making tasks that were complex in JavaScript easier to do. 

To put it simply, jQuery is just a collection of prewritten JavaScript code that will allow developers to:

• Select and manipulate HTML elements more easily than writing the code.
• Help developers manage user interactions, like clicks and form submissions.
• jQuery also creates smooth animations and effects, possible with minimal code.
• Make the websites and apps interactive in a more user-friendly and easy way.

jQuery became the most widely used JavaScript library after its release in 2006. jQuery’s motto, “Write less, do more”, is what it provides its developers.

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Why Use jQuery in Modern Development?

jQuery was released in 2006, but a good number of developers still use it despite the rise of modern frameworks like React and Vue.js. This is because jQuery offers:

1. Simplicity: jQuery has a very simple, easy-to-understand syntax that allows developers to quickly understand what they can do using the jQuery framework. jQuery makes it easier to manipulate web page content, capture user actions, and send data to web servers.
2. Cross-browser compatibility: This is one of the key features of jQuery, as it works smoothly on all major web browsers. You can write your code once, and it will behave consistently on Chrome, Firefox, Safari, and Edge. This saves time, and no special code is needed for each.
3. Large community: As a product that has been around for many years, jQuery has many usable resources, such as detailed documentation, plugins that will add extra functionality, and a sizeable community that helps with problem-solving. All of these resources add up to be very helpful to facilitate learning and using jQuery more easily and quickly.
4. Quick prototyping: If you need to build interactive features quickly, such as animations, slideshows, or form handling, jQuery can help you do that with very little code. This makes it ideal for quickly creating working versions of websites or testing out ideas before building a full application.
5. Legacy support: Many older websites still use jQuery. If you are updating or fixing such websites, it’s often easier to continue using jQuery rather than replacing it. Also, jQuery can be used alongside modern tools and frameworks, so you can combine old and new code without issues.

How to Include jQuery in Your Project

Before you can use jQuery, you need to include it in your HTML document. There are two main ways to do this:

1. Using the jQuery CDN

The easiest way to include jQuery is through a Content Delivery Network (CDN). A CDN is a network of servers located around the world that deliver files like jQuery quickly to users. When you use a CDN, your website can load jQuery from a server that is geographically closer to the visitor, which improves speed and performance. It also saves you from having to host the jQuery file yourself.

<script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>

What are the Benefits of using jQuery CDN?

• When using a CDN, jQuery is fetched directly from the source, ensuring the latest version is always loaded.
• CDNs use globally distributed servers, so users download jQuery from the nearest location for faster page loads.
• You don’t have to store jQuery on your own server, reducing server load and saving storage space.
• Using a CDN means you automatically get the most recent jQuery updates, including important security fixes.

2. Downloading and Hosting jQuery Locally

If you want to have better control over the jQuery used in your project or get offline functionality, you should download jQuery and host it locally. The steps to download and use it in your project are given below. 

Step 1: Go to the official jQuery website to download the most recent and stable version of the library.

Step 2: Select the minified version for performance or the uncompressed version for easier reading and debugging during development.

Step 3: After downloading, store the jQuery file in your project’s directory where other assets like CSS are located.

Step 4: The final step is to include the jQuery file. You can do this by using a <script> tag in your HTML file to load the jQuery file and enable its features.

<script src="js/jquery-3.7.1.min.js"></script>

When to use local hosting?

• Projects without internet connectivity: Local hosting is ideal when your project needs to run offline or in environments without stable internet access.
• Better performance for high-traffic sites: For websites with heavy traffic, hosting jQuery locally can reduce dependency on external servers and improve reliability.
• Complete control over library versions: By hosting jQuery yourself, you ensure full control over which version is used and when it’s updated.

Basic jQuery Syntax for Beginners

Now that we have successfully downloaded or connected jQuery in our HTML files, let us understand how to use it. Understanding jQuery syntax is important to use it correctly in your projects without throwing any errors. The basic structure follows the following pattern:

$(selector).action()

• $: The dollar sign is shorthand for the jQuery function, and it tells the browser that the next line should be treated as jQuery.
• Selector: It tells jQuery what part of the HTML you want to work with. For example: $(“p”) selects all <p> elements.
• . (dot operator): The dot (.) is used to access a method or function on the object returned by the selector.
• action(): This is the method or action you want to apply to the selected element(s). For example, you may use $(“p”).hide() to hide all the “p” elements. 

Document Ready Function

Document-ready functions are the most important concept in jQuery. This ensures your jQuery code runs only after the HTML document is fully loaded. It is the foundation of every jQuery script. The syntax you write to make your jQuery a document-ready function is 

$(document).ready(function(){
   // Your jQuery code goes here
});

There is another, shorter syntax version of this, which is:

$(function(){
   // Your jQuery code goes here
});

Manipulating HTML and CSS with jQuery

Now that you understand the basic jQuery syntax ($(selector).action()), let’s explore one of jQuery’s most sought-after DOM manipulation methods. 

The DOM (Document Object Model) represents the structure of your web page. With jQuery, you can easily change content, attributes, and styles on the fly, making your pages more dynamic and interactive.

Changing Content and Attributes

jQuery provides simple methods to update the text, HTML content, and attributes of elements.

• Change Text Content: This syntax replaces the text inside an element with ID heading, without affecting its HTML structure.

$("#heading").text("New Heading Text");

• Change HTML Content: The syntax below replaces the inner HTML of the element with ID content, allowing you to insert formatted content.

$("#content").html("<p>New paragraph with <strong>bold</strong> text</p>");

• Get Attribute Value: You can use this particular syntax to retrieve the href value of the first <a> tag on the page.

var linkUrl = $("a").attr("href");

• Set Attribute Value: This changes the src attribute of all <img> tags to a new image URL.

$("img").attr("src", "new-image.jpg");

Adding and Removing Classes

The jQuery addClass functionality is important for dynamic styling. Dynamic styling refers to changing the appearance of elements (like colors, fonts, or visibility) using code while the webpage is running.

• To add a class you use, $(".button").addClass("active");
• To remove a class, you use $(".button").removeClass("inactive");
• To toggle a class, toggle means to add if not present and remove if present. You can use $(".menu").toggleClass("open");
• And, finally, to add multiple classes, use $(".element").addClass("class1 class2 class3");

Let’s discuss this with the help of a practical example.

HTML Code:

<button class="btn default">Button 1</button>
<button class="btn default">Button 2</button>
<button class="btn default">Button 3</button>

CSS Code:

.default {
  background-color: lightgray;
  color: black;
}
.clicked {
  background-color: green;
  color: white;
}

JavaScript Code:

$(".btn").click(function() {
  $(".btn").removeClass("clicked").addClass("default");
  $(this).addClass("clicked").removeClass("default");
});

Output:

Explanation:

At first, all the classes are in the default classes. You can also confirm this by the gray color of each button. When a button is clicked:

1. First, the clicked class is removed from all buttons to reset them, meaning to turn them gray.
2. Then, we add the clicked class to the button that was clicked using $(this). It is done only for the clicked button. 

This is a simple way to highlight the active button while keeping others in their default state. This option is good for the ease of users of the website.

Handling Events in jQuery

Manipulating HTML and CSS often goes hand in hand with handling events, because user actions like clicks, mouse movements, or form inputs trigger changes on your page.

jQuery makes working with these events straightforward.

1. Click events let you run code when users click buttons or other elements. For example, we have given a code snippet that utilizes click events:

$("#button").click(function(){
    alert("Button was clicked!");
});
$(".menu-item").click(function(){
    $(this).addClass("selected");
    $(".content").fadeIn();
});

2. Hover events respond when users move their mouse over or away from elements. You can code that using the following code:

$(".card").hover(
    function(){
        $(this).addClass("hover-effect");
    },
    function(){
        $(this).removeClass("hover-effect");
    }
);

3. Form input events track user typing or form submissions:

$("#search").keyup(function(){
    var searchTerm = $(this).val();
    console.log("User typed: " + searchTerm);
});
$("#myForm").submit(function(e){
    e.preventDefault();
    // Add your custom form handling code here
});

4. Writing Cleaner Event-Based Code with Event Delegation

Sometimes, you add elements to your page dynamically after it loads. In those cases, it may not work as expected. Event delegation helps by attaching handlers to a parent element that listens for events on child elements, even if they are added later.

$(document).on("click", ".dynamic-button", function(){
    $(this).toggleClass("active");
});

This example listens for clicks on any element with class dynamic-button, even if those elements are added after the page initially loads. When clicked, it toggles the active class on that element.

Limitations of jQuery

While it is easy to learn and very useful for many tasks, it has some limitations you should be aware of as you grow your skills:

• Not always the best choice for large, complex Apps: It works great for small to medium projects, but bigger applications often need more structure and features that modern frameworks like React, Angular, or Vue provide.
• Performance can be slower compared to modern JavaScript: Native JavaScript (also called vanilla JS) has improved a lot and can sometimes run faster than this framework, especially when handling many elements or complex interactions.
• Adding jQuery adds extra file size: Including this script means loading an additional library, which can slow down your website, especially on slow connections or mobile devices.
• Less popular in new projects: Many new projects now prefer modern JavaScript frameworks or vanilla JavaScript, so it has now become less common in cutting-edge web development.
• Limited support for component-based architecture: It manipulates the DOM directly but doesn’t offer built-in ways to manage reusable UI components or state, which are important in modern development.

Despite these limitations, it remains a valuable tool for learning and for many existing projects, especially for simple tasks and quick prototyping.

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Conclusion

jQuery is a valuable tool for both beginners and experienced developers. Its simple syntax and powerful features make web development easier. You can add jQuery easily using a CDN or local hosting. It helps you change page content and handle user actions smoothly. With many plugins like DataTables, it lets you can add extra features effortlessly. Whether building a simple website or a complex app, jQuery provides tools to create engaging, interactive experiences. Practice regularly and explore the official documentation to master this essential library.

Introduction to JQuery – FAQs