var normalImage = new Array();
var hoverImage = new Array();
var downImage = new Array();

function preloadButtons(buttonList)
{
  var buttonArray=buttonList.split(",");
  
  for (var i = 0; i < buttonArray.length; i++) 
  {
    normalImage[buttonArray[i]] = new Image();
	normalImage[buttonArray[i]].src = 'images/btn/' + buttonArray[i] + '.jpg';
    hoverImage[buttonArray[i]] = new Image();
    hoverImage[buttonArray[i]].src = 'images/btn/' + buttonArray[i] + '-h.jpg';
    downImage[buttonArray[i]] = new Image();
    downImage[buttonArray[i]].src = 'images/btn/' + buttonArray[i] + '-d.jpg';
  }
}

function changeImage(buttonName)
{ 
  document.images[buttonName].src= hoverImage[buttonName].src;
  return true;
}
function changeImageBack(buttonName) 
{
   document.images[buttonName].src = normalImage[buttonName].src;
   return true;
}
function handleMDown(buttonName)
{
	document.images[buttonName].src = downImage[buttonName].src;
	return true;
}
function handleMUp(buttonName)
{
	changeImage(buttonName);
	return true;
}