// JavaScript Document
function createSocket(){
	//set up the socket
	var xmlHttp;
	try{ 
		// Firefox, Opera 8.0+, Safari  
		xmlHttp=new XMLHttpRequest();  
	}catch (e){
		// Internet Explorer
		try{
			xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");    
		}catch (e){
			try{
				xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");      
			}catch (e){
				return false;
			}
		}
	}
	return xmlHttp;
}
function checkSocket(obj){
	try
	{
		if (obj == false) return false;
	}catch(e)
	{
		if (e == "[object Error]"){
			//we got the object, continue
		}else{
			return false;
		}
	}
	return true;
}

function keepAlive(){
	var xmlHttp = createSocket();
	if (checkSocket(xmlHttp) == false) return;
	xmlHttp.onreadystatechange=function(){
		if(xmlHttp.readyState==4) {
			var t=setTimeout("keepAlive();",720000);		
		}
	}
	xmlHttp.open("GET","ajax/keep_alive.php",true);
	xmlHttp.send(null);
}