var ticks = 0;
var xmlHttp;
CheckServer();

setInterval("CheckServer()", 3000);

function CheckServer()
{   
  xmlHttp=GetXmlHttpObject();  
  if (xmlHttp==null)
  {
    alert ("Your browser does not support AJAX!");
    return;
  }   
  var url="/admin/GetDate.aspx";
  xmlHttp.onreadystatechange=stateChanged;
  xmlHttp.open("GET",url,true);  
  xmlHttp.send(null);
}

function stateChanged() 
{   
  if (xmlHttp.readyState==4)
  {     
    if (ticks == 0) {
      ticks = xmlHttp.responseText;
    }
    var diff = xmlHttp.responseText - ticks;
    //document.getElementById("test").innerHTML=ticks;  
    if (diff > 0) {
     location.reload(true);
    }
  }
}

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;
}