/******************************************** 
 *      简单ajax调用,使用说明               *
 *   var obj = new AJAXRequest();           *
 *   obj.method="get";                      *        
 *   obj.url = "test.asp?action=test";      *
 *   obj.callback = function (xmlhttp) {}   *
 *   obj.send();                            *
 ********************************************/
function AJAXRequest() { 
    var xmlObj = false; 
    var CBfunc,ObjSelf; 
    ObjSelf=this; 
    try { xmlObj=new XMLHttpRequest; } 
    catch(e) { 
        try { xmlObj=new ActiveXObject("MSXML2.XMLHTTP"); } 
        catch(e2) { 
            try { xmlObj=new ActiveXObject("Microsoft.XMLHTTP"); } 
            catch(e3) { xmlObj=false; } 
        } 
    } 
    if (!xmlObj) return false; 
    this.method="POST"; 
    this.url; 
    this.async=true; 
    this.content=""; 
    this.callback=function(cbobj) {return;} 
    this.send=function() { 
        if(!this.method||!this.url||!this.async) return false; 
        xmlObj.open (this.method, this.url, this.async); 
        if(this.method=="POST") xmlObj.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
        xmlObj.onreadystatechange=function() { 		
            if(xmlObj.readyState==4) {
                if(xmlObj.status==200) {
                    ObjSelf.callback(xmlObj); 
                } 
            } 
        } 
        if(this.method=="POST") xmlObj.send(this.content); 
        else xmlObj.send(null); 
    } 
}