var xmlhttp

function callurl(mUrl,returnfunc)
{ 
  xmlhttp= getxmlhttp();
  if (xmlhttp==null)
  {
    alert ('Browser does not support http Request');
    return;
  } 
  var url=mUrl;
  url=url+'?sid='+Math.random();
  xmlhttp.onreadystatechange= eval(returnfunc);
  xmlhttp.open('GET',url,true);
  xmlhttp.send(null);
}

function checkReady(obj)
{
  if(obj.readyState==4)
  {
    if(obj.status==200)
    {
      return true;
    }
    else
    {
      alert('Problem retrieving XML data');
    }
  }
}

function getxmlhttp()
{
var http_request;

if (window.XMLHttpRequest) { 
	http_request = new XMLHttpRequest();
	if (http_request.overrideMimeType) {
		http_request.overrideMimeType('text/xml');
	}
} else if (window.ActiveXObject) { 
	try {
		http_request = new ActiveXObject('Msxml2.XMLHTTP');
	} catch (e) {
		try {
			http_request = new ActiveXObject('Microsoft.XMLHTTP');
		} catch (e) {}
	}
}
return http_request
}