function displayAlert()
	{	
		closeAlert();

		var a = document.getElementById("alertshadow");
		a.style.display = 'block';
		a.style.left = (window.screen.width - 450) / 2;
		
		a = document.getElementById("alertinfo");
		a.style.display = 'block';
	}
	function displayStop()
	{	
		closeAlert();
		
		var a = document.getElementById("alertshadow");
		a.style.display = 'block';
		a.style.left = (window.screen.width - 450) / 2;

		a = document.getElementById("alertstop");
		a.style.display = 'block';
	}
	function closeAlert()
	{
		document.getElementById("alertshadow").style.display = 'none';
		document.getElementById("alertinfo").style.display = 'none';
		document.getElementById("alertstop").style.display = 'none';
	}
	function displayAlertStart()
	{	
		var a = document.getElementById("alertstartshadow");
		a.style.display = 'block';
		a.style.left = (window.screen.width - 450) / 2;
		var b = document.getElementById("leftpos");
		b.value = (window.screen.width - 450) / 2;
	}
	function closeAlertStart()
	{
		document.getElementById("alertstartshadow").style.display = 'none';
	}