ajax提交的javascript代码

var xhr=xhr();

function xhr(){

if(window.XMLHttpRequest){

return   window.XMLHttpRequest();

}else if(window.ActiveXObject){

return new ActiveXObject("Microsoft.XMLHTTP");

}catch(e){

try{

return new ActiveXObject("Msxml2.XMLHTTP");

}catch (ex){}

}

}

}

xhr.open("get","url","true");

xhr.onreadystatechange=function(){

if(xhr.readyState==4&&(xhr.status==200||xhr.status==304)){

document.getElementById("myDiv").innerHTML=xhr.responseText;

}

}

xhr.send();