var map = Array();

var imgValidity = Array();

function over(id, src) {
	// Save the old image src
	if(!map[id])
		map[id] = document.getElementById(id).src;
	
	// Check if the new image src is valid
	var i = new Image();
	i.src = src;
	if(!imgValidity[src]) {
		if(i.height > 0)
			imgValidity[src] = true;
		else
			imgValidity[src] = false;
	}
	if(imgValidity[src])
		document.getElementById(id).src = src;
}

function out(id) {
	delay('outHelper(\"' + id + '\")');
}

function outHelper(id) {
	document.getElementById(id).src = map[id];
}

function down(id) {
	document.getElementById(id).src = "dow_" + document.getElementById(id).substring(4);
}

function delay(func) {
	setTimeout(func, 150);
}

var rimgs = Array();
function preload(imgs) {
	for(var i = 0; i < imgs.length; i += 1) {
		var im = new Image();
		im.src = imgs[i];
	}
}