Write a simple Ajax operation class

<Script language = "JavaScript">
//-----------------------------------
// Description: simple Ajax operation class
// Author: no_miss
// Createtime: 2006.06.06
// Lastupdatetime: 2006.08.02
//-----------------------------------

Function Ajax (){
This. method;
This. url;
This. responsetype;
This. content;
VaR http_request = false;
This. getexecobj = function (revalue ){
If (window. XMLHttpRequest ){
Http_request = new XMLHttpRequest ();
If (http_request.overridemimetype ){
Http_request.overridemimetype ("text/XML ");
}
}
Else if (window. activexobject ){
Try {
Http_request = new activexobject ("msxml2.xmlhttp ");
} Catch (e ){
Try {
Http_request = new activexobject ("Microsoft. XMLHTTP ");
} Catch (e ){}
}
}
If (! Http_request ){
Window. Alert ("An error occurred while creating the XMLHTTPRequest object instance .");
Return false;
}

If (this. method. tolowercase () = "get "){
Http_request.open (this. method, this. url, true );
}
Else if (this. method. tolowercase () = "Post "){
Http_request.open (this. method, this. url, true );
Http_request.setrequestheader ("Content-Type", "application/X-WWW-form-urlencoded ");
}
Else {
Window. Alert ("the HTTP request type parameter is incorrect. ");
Return false;
}
Http_request.send (this. content );

VaR retextresponse = function (){
If (http_request.readystate = 4 ){
If (http_request.status = 200 ){
Revalue (http_request.responsetext );
} Else {
Alert ("the page has an exception. ");
}
}
}
VaR rexmlresponse = function (){
If (http_request.readystate = 4 ){
If (http_request.status = 200 ){
Revalue (http_request.responsexml );
} Else {
Alert ("the page has an exception. ");
}
}
}

If (this. responsetype. tolowercase () = "text "){
Http_request.onreadystatechange = retextresponse;
}
Else if (this. responsetype. tolowercase () = "XML "){
Http_request.onreadystatechange = rexmlresponse;
}
Else {
Window. Alert ("parameter error. ");
Return false;
}
}
}


// Call Method
VaR _ Ajax = new Ajax ()
_ Ajax. method = "Post"; // whether it is get or post
_ Ajax. url = "http://aaa.com/a.asp"; // request address
_ Ajax. responsetype = "text"; // type of the returned content
_ Ajax. content = "id = 1"; // sent content
_ Ajax. getexecobj (function (STR) {document. getelementbyid ("AAA"). innerhtml = STR}); // process the returned value

</SCRIPT>
<Div id = "AAA"> </div>