function centresite(objectID)
			{
			var leftpos = 0;
			var elementwidth = 1000;
			var elementheight = 600;
			var browserwidth =  document.body.clientWidth;
			var browserheight =  document.body.clientHeight;
			leftpos = (browserwidth - elementwidth)/2;
			toppos = (browserheight - elementheight)/2;
			if (leftpos < 0) {leftpos = 0;}	
			if (toppos < 0) {toppos = 0;}	
			document.getElementById(objectID).style.left = leftpos+"px";
			document.getElementById(objectID).style.top = toppos+"px";	
			}