function getElementByClass(node, classname, tag) {
	var classElements = new Array();
	if (node==null) node=document;
	if (tag==null) tag='div';

	var els = node.getElementsByTagName(tag);

	var pattern = new RegExp("(^|\s)"+classname+"(\s|$)");

	for (var i=0, j=0; i<els.length; i++) {
		if (pattern.test(els[i].className)) {
			classElements[j] = els[i];
			j++;
		}
	}
	return classElements[0];
}

function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function swapImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<arguments.length; i+=2) {
			document.getElementById(arguments[i]).src = arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		kenko_11_down = newImage("../images/kenko_11-down.gif");

		preloadFlag = true;
	}
}

function hoverOn(id) {
	var bgColor, txtColor; 
	switch (id.className) {
		case "top": bgColor="#666"; txtColor="#fff"; break; 
		case "cat": bgColor="#9cf"; txtColor="#039"; break; 
		case "art": bgColor="#cef"; txtColor="#039"; break; 
	}

	id.style.backgroundColor = bgColor; 
	id.style.color = txtColor;
}

function hoverOff(id) {
	var txtColor; 
	switch (id.className) {
		case "top": txtColor="#000"; break; 
		case "cat": txtColor="#039"; break; 
		case "art": txtColor="#039"; break; 
	}

	id.style.backgroundColor = ""; 
	id.style.color = txtColor;
}


function toggleMenu(parent, obj) { 
	var layerName = getElementByClass(parent, obj);
	layerName.style.display = (layerName.style.display=="none") ? "" : "none"; 
}

function toggleLayer(obj) { 
	var layerName = document.getElementById(obj);
	layerName.style.display = (layerName.style.display=="none") ? "" : "none"; 
}