JQuery is a JavaScript Library. It simplifies JavaScript programming. It is a lightweight. It takes a lot of common tasks that require many lines of JavaScript code to accomplish, and wraps them into methods that you can call with a single line of code. It also simplifies a lot of the complicated things from JavaScript, like AJAX calls and DOM manipulation.
The jQuery library contains the following features:
- HTML/DOM manipulation
- CSS manipulation
- HTML event methods
- Effects and animations
- AJAX
- Utilities
Downloading jQuery
There are two versions of jQuery available for downloading:
- Production version – this is for your live website because it has
been minified and compressed. - Development version – this is for testing and development
(uncompressed and readable code).
The jQuery library is a single JavaScript file, and you reference it with the HTML tag (notice that the tag should be inside the section):
<head>
<script src="https://stackoverflow.com/questions/40409660/jquery-3.1.1.min.js"></script>
</head>
jQuery CDN
If you don’t want to download and host jQuery yourself, you can include it from a CDN (Content Delivery Network).
Both Google and Microsoft host jQuery.
To use jQuery from Google or Microsoft, use one of the following:
Google CDN:
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
</head>
Microsoft CDN:
<head>
<script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.1.1.min.js"></script>
</head>
One big advantage of using the hosted jQuery from Google or Microsoft:
Many users already have downloaded jQuery from Google or Microsoft when visiting another site. As a result, it will be loaded from cache when they visit your site, which leads to faster loading time. Also, most CDN’s will make sure that once a user requests a file from it, it will be served from the server closest to them, which also leads to faster loading time.
You can learn more about JQuery from http://www.w3schools.com/jquery/default.asp