var imagesLoaded = null
var imgArray = new Array()
var itemID = "item_";
var onID = "_on";

// button object ////////////////////////////////////////////////////////////////////////
function Button(ref,srcon,srcoff){
	this.ref = ref // reference to the image object
	this.srcon = srcon // source of the mouseover image
	this.srcoff = srcoff // source of the mouseout image
	// preloading mouseover
	this.imgObj = new Image()
	this.imgObj.src = srcon
}

// preload function /////////////////////////////////////////////////////////////////////
function preload(){
	var docImages = document.images
	for (var i=0;i<docImages.length;i++) {
		if(docImages[i].src.indexOf(itemID) != -1 && docImages[i].src.indexOf(onID) == -1) {
			imgArray[docImages[i].name] = new Button(docImages[i],docImages[i].src.substring(0,docImages[i].src.length-4) + onID + docImages[i].src.substring(docImages[i].src.length-4),docImages[i].src)
		}
	}
	imagesLoaded = 1
}

// highlight buttons ////////////////////////////////////////////////////////////////////
function imageOn(name){
	if(imagesLoaded){
		var obj = imgArray[name].ref
		obj.src = imgArray[name].srcon
	}
}

function imageOff(name){
	if(imagesLoaded){
		var obj = imgArray[name].ref
		obj.src = imgArray[name].srcoff
	}
}