Introduction to jQuery | Basics

Jquery is a JavaScript library for writing JavaScript files.
The extension of Jquery file is <file_name>.js.
The variable which is globally available is the $ variable,
You can make AJAX call using jQuery.
The syntax is $.ajax() function
To access the document object in JQuery, use the $(document).
To add an event handler use the $ (document). ready (function() {});
To add animation we use the animate() method on the CSS selector

The $(dollar) function takes a string as an input and the string should abe a valid CSS selector and creates callback fuctions whenevere a method call or callback processing is required. Examples are as follows:
$("p.first") This will return all the paragraph (<p>) elements whose class attribute is equal to the value "first".
$("#test") This will return the HTML eleemnt whose id attribute is "test"