// hide layer definitions
	
	function showDivLayers(toshow) {
		for (i=1;i<=5;i++) {
			layer = "library_" + i;

			if (i == toshow && document.getElementById(layer).style.display == "none") { 
				document.getElementById(layer).style.display = "block";
				}
			else {
				document.getElementById(layer).style.display = "none";
				}
			}
	}