var mrtimeoffset;
var mrclocktimeout;

var MR_CLOCKREFRESHTIME=500;     //in millis
var MR_PREFIX="Time Vienna: ";   // what to show in front of clock
var MR_DIV_ID="mrclock";  // constant, leading to div-container 
var MR_AJAXURL="/fileadmin/clock/clocksrv.php";  // constant, leading to div-container 
var mrtimeoffset=0;

function ajaxread() 
{ 
	var ajaxread; 
	try { ajaxread=new XMLHttpRequest(); } 
	catch (e) { 
	   try { ajaxread=new ActiveXObject("Msxml2.XMLHTTP"); } 
            catch (e) { 
               try { ajaxread=new ActiveXObject("Microsoft.XMLHTTP"); } 
               catch (e) {return false;} 
            } 
         } 
         
         ajaxread.onreadystatechange=function() 
	{ 
	   if(ajaxread.readyState==4) { 
   	       var servertime=new Date(ajaxread.responseText);
	       mrtimeoffset=new Date().getTime()-servertime.getTime()-500;
	       displaytime();
             } 
          }
           
	ajaxread.open("GET",MR_AJAXURL,true); //the name of the file that needs to be inserted into the division in this case its clock.php
 	ajaxread.send(null); 

} 





function displaytime(){


	var t=new Date().getTime()-mrtimeoffset;
	var realtime=new Date(t);
	
	document.getElementById(MR_DIV_ID).innerHTML=	MR_PREFIX+
	                                    realtime.getHours()+":"+
	                                    leadzero(realtime.getMinutes())+":"+
	                                    leadzero(realtime.getSeconds());

	mrclocktimeout=setTimeout("displaytime()",MR_CLOCKREFRESHTIME);
}
	

	
function leadzero(s) {
	if (s<10) { return "0"+s;} else {
	return s;
	}
}	
	
window.onload=function(){
        ajaxread();
	
      
		
}
window.onunload=function(){
	clearTimeout(mrclocktimeout);
}