jQuery main function is the ‘$(document).ready() function’. Although it’s many way to start jQuery, Always use this function to start using jQuery is good. example:

$(document).ready(function() {
$('.header-company').addClass('highlight');
});

This will add class named ‘highlight’ to element that have ‘header-company’ class. This is used generally for changing / adding class for CSS. So, when the document was loaded, the jQuery command will add the CSS Style.

jQuery provides many general function to build a rich pages. jQuery feature:

• Ajax
  jQuery is one of the ajax framework that used mostly by many web master.
• Shortcut access to DOM
  instead of using bulk of code in accessing DOM, jQuery have the shortcut.
• Manipulating the element content
  With jQuery, we can freely insert, update and delete every HTML element.
• Easy event handling
  Event handling is no fear again in web pages, jQuery make the process simple.
• Animation
  by default, jQuery already have ability to perform general animation on the pages.
• Action Chaining
  Instead of using many temporary variable and repetition lines, we can easily unite several lines of code that have same characteristic to a line code with chaining.
• CSS Compliance
  The jQuery selector is CSS Compliance, that make any designer that already have knowledge about CSS is able to learn jQuery easily.
• Cross browser
  using jQuery, no more hack for IE… the framework has done it automatically.

jQuery is created by John Resig, it is a powerful JavaScript library that can rock and enhance your websites. jQuery is provides very wide range of features, easy-to-use syntax, and great cross-platform compatibility in a single file.

Another jQuery superiority is it has thousands of plugin that developed to extend jQuery’s functionality, the plugin make jQuery as an essential tool. Mastering jQuery allow you to add attractive interactions and animations to your web with AJAX, events, effects, and advanced JavaScript language features.