Introduction to jQuery

jQuery is a web developer’s best friend when it comes to handling JavaScript tasks efficiently. If you have a good command of Java, getting used to the framework will be a piece of cake. If not, there isn’t much to worry about – jQuery is fairly straightforward and has a smooth learning curve.

The framework is supported by most JS integrated development environments – Eclipse, Visual Studio, and others. In this post, you will find out whether jQuery is still relevant, what its applications are, and will understand the difference between using the library and plain JavaScript.

What Is jQuery?

jQuery is a library geared at increasing the efficiency of event, CSS style, and Ajax handling. Out of 10 million most popular websites, 73% rely on the library to facilitate maintenance and ensure scalability. jQuery beats other JavaScript libraries in popularity by huge numbers, with the market share of 94% among JS users.

The fact that most websites – including Microsoft, Stack Overflow, and eBay – use jQuery proves that getting a good command of the library will be an additional boost to your CV in software engineering.

The library is free. You can download the full and compressed versions of jQuery on the official website. The difference between the packages is that the latter eliminates most white space, shortens function names, and variables. It’s not easy to read but is fully functional and uses fewer system resources.

How to Use jQuery?

There are two ways to integrate the library into the website code and manipulate its features:

  • Local installation – save jQuery to your local storage and add it to the HTML code of your website.
  • CDN usage – use a content delivery network to integrate the library into HTML. Using CDN instead of a local machine gives developers the power to process more requests, speeds up the network response, and reduces hoops by hosting data at data centers at different locations. If you are wondering which CDN to use, consider going with the options Google and Microsoft provide.

Top jQuery Applications

The library is one of the most multi-functional tool suites for JavaScript developers. It doesn’t fall short of potential uses – here are the most widely used jQuery applications:

1. Plugins

Plugins help automate or shorten the amount of time needed to implement website changes and tweaks. They contain useful jQuery methods and often come in handy for handling routine website maintenance tasks, such as:

  • Creating CSS animation
  • Handling Ajax;
  • Incorporating interface elements – sliders and others
  • Improving user navigation – implementing drag-and-drop, auto-resume, and other useful features
  • Embedding media files. 

You can see the full list of jQuery plugins in the official repository. All plugins are free to use.

2. Handling DOM elements

Document Object Model (in short, DOM) allows developers to navigate and manipulate XML or HTML files. Although standard JS features include tools for DOM manipulation, it’s a tiresome and inefficient process.

On the other hand, jQuery helps organize the process of DOM navigation and editing. Using a built-in selector engine (Sizzle), a developer can choose a needed DOM element, edit it, replace them, or insert new DOM files into an existing one.

3. Ensuring cross-platform accessibility

jQuery is one of the few JS libraries available for all major browser clients. Other than that, the platform supports CSS3 and X Path. jQuery can run effortlessly on Android and iOS browsers as well – developers don’t have to worry about low-responsiveness or usability bugs.

4. Creating animations and supporting Ajax

The library has dozens of off-the-shelf animation effects. Essentially, a developer will need to simply copy and paste the code to add visual tweaks to the website. Moreover, jQuery supports AJAX technology and helps developers ensure their feature-rich websites are responsive and user-friendly as well.

Developers use jQuery as a tried-and-true tool for building clean, modern, and easy to use webpages.

5. Speeding up the development process

jQuery helps developers write less JavaScript code without compromising the functionality of the page. The difference is drastic at times – you can shorten 25 lines of code to 5 by implementing the library instead of using plain JavaScript. Other than increasing the efficiency of development and maintenance, jQuery reduces memory usage by helping tech teams create smaller files.

jQuery vs JavaScript: Know The Difference

Keep in mind that comparing jQuery and JavaScript as separate entities is not technically correct since the former is not a programming language. However, understanding how implementing jQuery is different from using JS alone can help developers decide whether or not they should choose the library for the next projects.

The key differences between jQuery and JavaScript are outlined in the table below:

jQueryJavaScript
A JavaScript libraryA programming language
Is designed to facilitate DOM handling, Ajax implementation, event handling, and creating CSS animations.Is scripted, helps implement interface interactions and control the content of HTML documents
Is based on the resources JavaScript providesIs an interpreted language
Developers don’t need to write much scripting on their own – jQuery offers ready-to-deploy scriptsDevelopers need to write scripts from scratch
Is cross-browser, there’s no need to worry about compatibility concernsDoesn’t ensure browser compatibility – developers need to write scripts to make the page accessible across different clients
Fewer lines of codeMore lines of code during development
Well-suited for managing complex, high-traffic websites where a developer has a high risk of making mistakes.More flexibility, faster DOM accessibility

These were the main differences between jQuery and plain JavaScript. Choosing whether or not you want to use the library depends on your JS mastery. While more experienced developers can get by without it, beginners should consider integrating jQuery to reduce the odds of failure.

jQuery Syntax

Actions and Selectors

jQuery syntax consists of two main components – selectors and actions. Thus, the standard look of jQuery code is as follows:

$(selector).action()

Let’s break down its components:

  • Developers use a $ sign to access jQuery
  • A selector helps specify HTML elements a developer will be working with
  • action() defines which actions will be performed on a selected HTML component.

If a developer has a good command of CSS, getting the hang of jQuery will not be difficult since the library shares the syntax with the styling language.

Some examples of jQuery’s practical uses are:

$(this).hide() – hides a chosen HTML element

$(“.classname”).hide() – hides all elements within a chosen class.

Document-Ready Events

All jQuery methods we used as an example are applied only once the JS document is fully loaded. A developer should insert jQuery lines after a $(document).ready(function(){

This way, you can ensure that methods will not run before the JavaScript is loaded completely. Other than that, such a practice allows developers to load all JS content before the body of the page.

If you want to declare document-ready events in a more concise way, you can use this code, created by the jQuery team:

$(function(){

// Insert jQuery methods

})

Examples of jQuery – Methods Developers Should Be Using

When you are through with the introduction to jQuery, it wouldn’t hurt to broaden your jQuery vocabulary by memorizing some useful methods. Here is the list of methods that will come in handy no matter what type of JS project you are building.

before()/after()

This method is useful for efficient DOM handling since it helps insert elements inside the DOM with no hooks. It’s a solid alternative to append()/prepend(). The element you inserted after a chosen HTML element will become its sibling.

Here’s the general look of the method:

$('#nameofelement').after($('nameofelement)).text());
$('#nameofelement').before($(nameofelement')).text());

data()/removedata()

This method facilitates data storage and helps developers store additional info about code elements. You can either use objects or key-value pairs as inputs. Similarly, a developer can use removedata() to delete the values stored about the element.

$('objectname').data('keyName', 'valueName');
$('objectname).removedata('keyName', 'valueName);

get()

If you want to see a jQuery element as a raw DOM element, you can use get() to return it. Here’s how a developer can apply the method:

alert( $('p').get(objectname) );

change()

Change is a helpful event handler – you can use to change the target of text inputs, select boxes, or textareas. The firing mechanism is a key difference between change() and blur() or focus() – the latter fire when the element is no longer in focus, regardless of a value change.

Take a look at a practical way to apply change():

$(input[type=datatype]).change(function() {
//Insert validation code
})

queue()/dequeue()

This method is a developer’s go-to when dealing with animations via jQuery. A queue refers to all the animations you want to execute on an element.

Take a look at the way queue() will look in the code:

$('div').queue('elementname', []);
});

$('#add').click(function() {
    $('div').queue( function(){
        $(this).animate({ height : '-=25'}, 2000);
        $(this).dequeue()

Pay attention that queue() requires a complementary dequeue() method once the list of animations attached to the elements is over.

Conclusion

jQuery is a lightweight yet sufficiently robust JavaScript library that gives developers a broad toolkit for event handling, DOM manipulation, and animation management. Granted, getting the hang of the tool will take time – however, in the long run, knowing how to use jQuery will help scale your projects more efficiently and avoid accidental development errors.

The quality of the end product will improve as well since jQuery promotes cleaner syntax, user-friendliness, and low system resource usage.

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