Create an XMLHTTPRequest object using Ajax

XMLHttpRequest is used to exchange data with the server in the background. This means that you can update a part of a webpage without reloading the entire webpage.

Create an XMLHTTPRequest object:

VaR XMLHTTP;
If (window. XMLHttpRequest)
{// Code for IE7 +, Firefox, chrome, opera, Safari
XMLHTTP = new XMLHttpRequest ();
}
Else
{// Code for IE6, ie5
XMLHTTP = new activexobject ("Microsoft. XMLHTTP ");

}

 

Ajax-send a request to the server:

To send requests to the server, we use the open () and send () Methods of the XMLHTTPRequest object, refer to: http://www.w3school.com.cn/ajax/ajax_xmlhttprequest_send.asp

xmlhttp.open("GET","test1.txt",true); xmlhttp.send();

 

 

Ajax-server response:

To obtain a response from the server, use the responsetext or responsexml attribute of the XMLHTTPRequest object. For details, refer:
Http://www.w3school.com.cn/ajax/ajax_xmlhttprequest_response.asp

Attribute	Description
Responsetext	Obtain response data in string format.
Responsexml	Obtain response data in XML format.

 

 

Ajax-onreadystatechange event

Reference: http://www.w3school.com.cn/ajax/ajax_xmlhttprequest_onreadystatechange.asp