jQuery simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development.
DOM manipulation − The jQuery made it easy to select DOM elements, traverse them and modifying their content by using cross-browser open source selector engine called Sizzle.
Event handling − The jQuery offers an elegant way to capture a wide variety of events, such as a user clicking on a link, without the need to clutter the HTML code itself with event handlers.
AJAX Support − The jQuery helps you a lot to develop a responsive and feature-rich site using AJAX technology.
Animations − The jQuery comes with plenty of built-in animation effects which you can use in your websites.
Lightweight − The jQuery is very lightweight library - about 19KB in size ( Minified and gzipped ).
Cross Browser Support − The jQuery has cross-browser support, and works well in IE 6.0+, FF 2.0+, Safari 3.0+, Chrome and Opera 9.0+
Latest Technology − The jQuery supports CSS3 selectors and basic XPath syntax.
There are two ways to use jQuery.
Local Installation − You can download jQuery library on your local machine and include it in your HTML code.
CDN Based Version − You can include jQuery library into your HTML code directly from Content Delivery Network (CDN).
Go to the https://jquery.com/download/ to download the latest version available.
Now put downloaded jquery-2.1.3.min.js file in a directory of your website, e.g. /jquery.
Now you can include jquery library in your HTML file as follows −
See this example:
You can include jQuery library into your HTML code directly from Content Delivery Network (CDN). Google and Microsoft provides content deliver for the latest version.
We are using Google CDN version of the library throughout this tutorial.
Now let us rewrite above example using jQuery library from Google CDN.
As almost everything we do when using jQuery reads or manipulates the document object model (DOM), we need to make sure that we start adding events etc. as soon as the DOM is ready.
If you want an event to work on your page, you should call it inside the $(document).ready() function. Everything inside it will load as soon as the DOM is loaded and before the page contents are loaded.
To do this, we register a ready event for the document as follows −
To call upon any jQuery library function, use HTML script tags as shown below −
Now we can include custom.js file in our HTML file as follows −