function showPopup(Url)
{
	var Width,Height;
	
	if(Width == null)
		Width = 700;
	if(Height == null)
		Height = 500;
		
	var x = screen.availWidth / 2 - (Width / 2);
	var y = screen.availHeight / 2 - (Height / 2);
		
	if(typeof(winHost) == "object")
		if(!winHost.closed)
			winHost.close();
			
	var strFeatures = "directories=no,location=no,menubar=no,resizable=no,scrollbars=no,status=no,toolbar=no,height=" + Height + ",width=" + Width + ",top="+y+",left="+x;
	winHost = window.open(Url, "winHost", strFeatures, true);
}