Write Ajax using native JS

//using native JS to encapsulate Ajax//compatible with XHR objectsfunctioncreatexhr () {if(typeofXMLHttpRequest! = "undefined") {//non-IE6 browser        return NewXMLHttpRequest (); }Else if(typeofActiveXObject! = "undefined") {//IE6 Browser        varVersion = [                    "msxml2.xmlhttp.6.0",                    "Msxml2.xmlhttp.3.0",                    "Msxml2.xmlhttp",        ];  for(vari = 0; i < version.length; i++){            Try{                return NewActiveXObject (Version[i]); }Catch(e) {//Skip over            }        }    }Else{        Throw NewError ("Your system or browser does not support XHR objects! "); }}//Escape Characterfunctionparams (data) {vararr = [];  for(varIinchdata) {Arr.push (encodeURIComponent (i)+ "=" +encodeURIComponent (Data[i])); }    returnArr.join ("&");}//Encapsulating AjaxfunctionGa_ajax (obj) {varXHR =createxhr (); Obj.url= Obj.url + "? rand=" + math.random ();//Clear CacheObj.data = params (obj.data);//Escape String    if(Obj.method = = = "Get") {//determine whether a Get method is used to sendObj.url + = Obj.url.indexOf ("?") = = "-1"? "?" + Obj.data: "&" +Obj.data; }    //Asynchronous    if(Obj.async = = =true){        //need to trigger onReadyStateChange event when asynchronousXhr.onreadystatechange =function(){            //execution Complete            if(Xhr.readystate = = 4) {callBack ();  }}} Xhr.open (Obj.method,obj.url,obj.async); //false is synchronous true is asynchronous//"demo.php?rand=" +math.random () + "&name=ga&ga",    if(Obj.method = = = "POST") {Xhr.setrequestheader ("Content-type", "application/x-www-form-urlencoded");    Xhr.send (Obj.data); }Else{xhr.send (NULL); }    //Xhr.abort ();//Cancel Asynchronous request    //Sync    if(Obj.async = = =false) {callBack (); }    //Return Data    functionCallBack () {//determine whether to return the correct        if(Xhr.status = = 200) {obj.success (xhr.responsetext); }Else{obj. Error ("Failed to get data, error code:" +xhr.status+ "error message:" +xhr.statustext); }    }}varhtml = document.getelementsbytagname ("html") [0];html.onclick=function() {Ga_ajax ({"Method": "Post",        "url": "Demo.php",        "Data" : {            "Name": "Gao",            "Age": 100,            "num": "12346&598"        },        "Success":function(data) {alert (data); },        "Error":function(text) {alert (text); },        "Async":false    });}

Write Ajax using native JS