AJAX - Technologies can not work independently

AJAX cannot work independently. It is used in conjunction with other technologies to create interactive web pages.

JavaScript

Freely typed writing language.  The JavaScript function is called when the event appears on the page. 

Keep all AJAX work.

DOM

Organized access and management API.  Represents the composition of XML and HTML documents. 

CSS

Allows clear separation of presentation style content and can be modified by JavaScript

XMLHttpRequest

A JavaScript object that enables different server interactions.