var xmlHttp1
function checkuname(str,str1)
{
xmlHttp1=GetXmlHttpObject()
if (xmlHttp1==null)
 {
 alert ("Browser does not support HTTP Request")
 return
 }
var url="validuser.php"
url=url+"?q="+str+"&w="+str1
url=url+"&sid="+Math.random()
xmlHttp1.onreadystatechange=stateChanged 
xmlHttp1.open("GET",url,true)
xmlHttp1.send(null)
}
function stateChanged() 
{ 
if (xmlHttp1.readyState==4 || xmlHttp1.readyState=="complete")
 { 
 document.getElementById("txtHint1").innerHTML=xmlHttp1.responseText 
 } 
}
function GetXmlHttpObject()
{
var xmlHttp1=null;
try
 {
 // Firefox, Opera 8.0+, Safari
 xmlHttp1=new XMLHttpRequest();
 }
catch (e)
 {
 //Internet Explorer
try
  {
  xmlHttp1=new ActiveXObject("Msxml2.XMLHTTP");
  }
 catch (e)
  {
  xmlHttp1=new ActiveXObject("Microsoft.XMLHTTP");
  }
 }
return xmlHttp1;
}