php栈溢出ajax

var xmlHttp;

function load()
{ 
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
 {
 alert ("Browser does not support HTTP Request");
 return
 }
var url="information.php";
url=url+"?&sid="+Math.random();
xmlHttp.onreadystatechange=stateChanged; 
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
setTimeout(load(),5000);
}

function stateChanged() 
{ 
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
 { 
 document.getElementById("txtHint").innerHTML=xmlHttp.responseText ;
 } 
}

function GetXmlHttpObject()
{
var xmlHttp=null;
try
 {
 // Firefox, Opera 8.0+, Safari
 xmlHttp=new XMLHttpRequest();
 }
catch (e)
 {
 //Internet Explorer
 try
  {
  xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
  }
 catch (e)
  {
  xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
 }
return xmlHttp;
}
怎么会栈溢出？

setTimeout(load(),5000);这个的问题