function checkScreen()
	{	
		var str;
		str="";
		if(is.ns4 || is.ie4)
			str="This site is designed to run with Internet Explorer 5 and above and Netscape 6 and above";
			
		//alert(screen.width+':'+screen.height+':'+screen.colorDepth+':'+screen.pixelDepth)
		if(is.ns4)
			var color=screen.pixelDepth
		else
			var color=screen.colorDepth
		if((screen.width!=800 && screen.height!=600) || color<16)
		{
			if(str!="")
				str+=" running at 800x600 with 16 bit colour.\nWe cannot gurantee the quality of this site with any other configuration."
			else
				str="This site is designed to run at 800x600 with 16 bit colour.\nWe cannot gurantee the quality of this site with any other configuration."
		}
		else	
			if(str!="")
				str+=".\n"
	
		if(str!="")
			alert(str)
	}