var xmlHttp

function showHint(str)
{
	if (str.length==0)
	{ 
		document.getElementById("txtHint").innerHTML="";
		return;
	}
	xmlHttp=GetXmlHttpObject();
	if (xmlHttp==null)
	{
		alert ("Your browser does not support AJAX!");
		return;
	} 

	var url="registration.php";
	url=url+"?Action=cities&city_name="+str;
	url=url+"&sid="+Math.random();
	xmlHttp.onreadystatechange=stateChanged;
	xmlHttp.open("GET",url,true);
	xmlHttp.send(null);
} 

function stateChanged() 
{ 
	if (xmlHttp.readyState==4)
	{ 
		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;
}