(function(){
//创建XMLHTTPRequest对象
function CreateXHR(){
if(window.XMLHttpRequest) return new XMLHttpRequest();
else if(window.ActiveXObject){
var aVersions = ["MSXML2.XMLHttp.6.0","MSXML2.XMLHttp.3.0"];
for(var i=0;i<aVersions.length;i++){
try{
var XHR = new ActiveXObject(aVersions[i]);
return XHR;
}catch(e){}
}
throw new Error("XHR can not be created");
}
}
var XHR = CreateXHR();//设置请求对象
function callback(){
if(XHR.readyState==4){
if(XHR.status==200){
[b]alert("run")//不运行[/b]
var message =newChilddocument.createElement("div");
message.innerHTML=XHR.responseText;
document.appendChild(message);
}
}
}
function submit(url,params,method){
XHR.onreadystatechange = callback;//设置回调函数
if(!method) method="get"
XHR.open(method,url,true);
XHR.send(params);
}
document.getElementById("submit").onclick=submit;
})()
帮我看一下为什么alert("run")不能运行
