javascript无刷新回传问题？

需求是这样的：看js代码。

var AllOrNone = ""

var setclassid = ""

var xmlHttpCheck;
try
{
xmlHttpCheck=new ActiveXObject("Msxml2.XMLHTTP");
}
catch(e)
{
try
{
  xmlHttpCheck=new ActiveXObject("Microsoft.XMLHTTP");  //老版本浏览器
}
catch(e)
{
  xmlHttpCheck=false;
}
}

if (!xmlHttpCheck && typeof (XMLHttpRequest)!='undefined')  //其它浏览器，如FF等...
{
xmlHttpCheck=new XMLHttpRequest();
}


function SetCurrentAll(classid)
{
setclassid = classid;

if(document.getElementById("chkClassid"+classid).checked==true)
{
AllOrNone = true;
}
else
{
AllOrNone = false;
}


if(AllOrNone == true)
{

var urlCheckAll="getboby.asp?classid="+escape(setclassid)+"&r=" + Math.random();

xmlHttpCheckAll.open("Get",urlCheckAll,true);

xmlHttpCheckAll.onreadystatechange=userbacknoteAll;

xmlHttpCheckAll.send(null);



document.getElementById("classid"+classid).className = "aa";
}
els