What is jQuery?

jQuery is a fast, small, and feature-rich JavaScript library. It makes things like HTML document traversal and manipulation, event handling, animation, and Ajax much simpler with an easy-to-use API that works across a multitude of browsers. With a combination of versatility and extensibility, jQuery has changed the way that millions of people write JavaScript.

Other Related Projects
jQueryUIjQuery Mobile
QUnitSizzle
Resources
jQuery Core API Documentation
jQuery Learning Center
jQuery Blog
Contribute to jQuery
About the jQuery Foundation
Browse or Submit jQuery Bugs
A Brief Look
DOM Traversal and Manipulation
Get the element with the class ‘continue’ and change its HTML to ‘Next Step…’
$( “button.continue” ).html( “Next Step…” )
Event Handling
Show the #banner-message element that is hidden with display:none in its CSS when any button in #button-container is clicked.

var hiddenBox = $( “#banner-message” );
$( “#button-container button” ).on( “click”, function( event ) {
hiddenBox.show();
});
Ajax
Call a local script on the server /api/getWeather with the query parameter zipcode=97201 and replace the element #weather-temp’s html with the returned text.

$.ajax({
url: “/api/getWeather”,
data: {
zipcode: 97201
},
success: function( result ) {
$( “#weather-temp” ).html( “” + result + " degrees" );
}
});