var xmlHttp

function showHint(str)
{

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

  xmlHttp=GetXmlHttpObject()

  if (xmlHttp==null)
    {
    alert ("ÄúµÄä¯ÀÀÆ÷²»Ö§³ÖAJAX£¡");
    return;
    }

  var url="ajax_search.asp";
  url=url+"?q="+escape(str);
 
  xmlHttp.onreadystatechange=stateChanged;
  xmlHttp.open("GET",url,true);
  xmlHttp.send(null);
} 

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