// JavaScript Document

//preload image

var i = new Image();
i.src = "img/download_over.png";

var offImages = [];
var overImages = [];
var elements = [];
var blankSrc = "blank.gif";

window.onload = function(){

	var downloadButton = document.getElementById("download");
	
	addRollOver(downloadButton, "img/download_over.png");

}

function addRollOver(el, overImageURL){
	
	elements.push(el);
	
	var originalSrc = el.src;
	
	if(el.runtimeStyle && el.runtimeStyle.filter.indexOf("AlphaImageLoader") != -1){
	var filter = el.runtimeStyle.filter.toString();
	var filterImage = /src='(.*)',/.exec(filter)[1];
	originalSrc = filterImage;
	//currentTarget.runtimeStyle.filter = "progid:DXImageTransform.Microsoft." + "AlphaImageLoader(src='" + newSrc + "',sizingMethod='scale')";

	}
	
	offImages.push(originalSrc);
	
	var i = new Image();
	i.src = overImageURL;
	
	overImages.push(i);
	
	el.onmouseover = doRollOver;
	el.onmouseout = doRollOut;
		
}

function matchElement(el){
	
	for (i = 0; i < elements.length; i++){
		
		if(elements[i] === el){
		return i;	
		}
		
	}
	
	return false;

}

function getCurrentTarget(e){
	var ev = e ? e : window.event;
	var currentTarget = ev.currentTarget ? ev.currentTarget : ev.srcElement;
	return [ev, currentTarget];
}

function doRollOver(e){
	
	var currentTarget = getCurrentTarget(e)[1];
	
	var elIndex = matchElement(currentTarget);
	
	currentTarget.src = overImages[elIndex].src;
	
}

function doRollOut(e){
	
	var currentTarget = getCurrentTarget(e)[1];
	
	var elIndex = matchElement(currentTarget);
	
	var newSrc = offImages[elIndex];
	
	currentTarget.src = newSrc;
	
	if(currentTarget.runtimeStyle && currentTarget.runtimeStyle.filter.indexOf("AlphaImageLoader") != -1){
	currentTarget.runtimeStyle.filter = "progid:DXImageTransform.Microsoft." + "AlphaImageLoader(src='" + newSrc + "',sizingMethod='scale')";
	currentTarget.src = blankSrc;
	}
}