var xmlHttp

function getPerformers(str)
{
if (str.length==0)
  { 
  document.getElementById("div_PInfo").innerHTML="";
  return;
  }
 xmlHttp = ""; // clear "xmlHttp" for reuse
xmlHttp=GetXmlHttpObject();
if (xmlHttp==null)
  {
  alert ("Your browser does not support AJAX!");
  return;
  } 
var url="ajax/getPerformers.php";
url=url+"?q="+str;
url=url+"&sid="+Math.random();
xmlHttp.onreadystatechange=stateChanged; // = xmlHttp.onreadystatechange=stateChanged(); - stateChanged is a function
//readyState property holds the status of the server's response. Each time the readyState changes, the onreadystatechange function will be executed//
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
} 

function stateChanged() 
{ 
/*
0	The request is not initialized
1	The request has been set up
2	The request has been sent
3	The request is in process
4	The request is complete
*/
if (xmlHttp.readyState==4)
{ 
document.getElementById("div_PInfo").innerHTML=xmlHttp.responseText;
document.getElementById("div_PInfo").style.visibility = "visible";
}
}

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;
}