function img_swap(img_name, img_src) {
	document[img_name].src = img_src; }
	
function top_zIndex(existingLayerID) {
	obj = document.getElementById(existingLayerID);
	if (typeof obj!="undefined") { obj.style.zIndex=50; } }
	
function orig_zIndex(existingLayerID) {
	obj = document.getElementById(existingLayerID);
	if (typeof obj!="undefined") { obj.style.zIndex=10; } }