// AJAX validacija korisničkog imena
// -------------------------------------------------------

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;
}


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


function UsernameCheck(str)
{
	if (str.length==0)
	{ 
		document.getElementById("txtCheck").innerHTML="";
		return;
	}

	xmlHttp=GetXmlHttpObject()
	if (xmlHttp==null)
	{
		alert ("Your browser does not support AJAX!");
  		return;
	} 
	
	var url="username_check.asp";
	url=url+"?username="+str;
	url=url+"&sid="+Math.random();
	xmlHttp.onreadystatechange=stateChanged;
	xmlHttp.open("GET",url,true);
	xmlHttp.send(null);
	
}