AJAX

Asynchronous JavaScript And XML

AJAX is a browser technology that is used to more interactive and fast web applications using XML, CSS , JavaScript and HTML.

AJAX   uses XHTML to content, CSS for decorate the presentation layer, DOM (Document Object Model ) and JavaScript for dynamic content display and functionality.   XML is used as the format for receiving server data.  XMLHTTPRequest  is a JavaScript object that performs the asynchronous interaction with the server. 

Normal web applications transmit data to the server and get data from the data from the server using synchronous requests. But when we use AJAX,  JavaScript will make a request to the server, interpret the result and update the current interface. Then the user will never notice anything was transmitted to the server.  AJAX is totally independence from the web server software.  

Steps of AJAX operations

·        Client event occurs

·        XMLHTTPRequest is created.

·        XMLHTTPRequest  is configured.

·        XMLHTTPRequest object makes an asynchronous request to the web server.

·        Web server returns the result containing XML document.

·        XMLHTTPRequest object calls the callback function and process the result.

·        HTML DOM is updated.