function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}

origin = 0;

function moveElement(elementID,final_x,interval) {
  if (!document.getElementById(elementID)) return false;
  var elem = document.getElementById(elementID);	
  if (elem.movement) {
    clearTimeout(elem.movement);
  }
  if (!elem.style.left) {
    elem.style.left = "0px";
  }
  var xpos = parseInt(elem.style.left);
  if (xpos==origin+final_x) {
		origin = xpos;
    return true;
  }
	
  if (!document.getElementsByTagName) return false;
	var dgallery = document.getElementById("discoveries_gallery");
	var dimages = dgallery.getElementsByTagName("img")
	for (var i=0; i<dimages.length; i++)
	maxScroll = (dimages.length)*90;
  if (xpos < (origin+final_x)) {   // previous link clicked
		if (origin!=0){
			var dist = Math.ceil(((origin+final_x) - xpos)/10);
			xpos = xpos + dist;
		}
  }
  if (xpos > (origin+final_x)) {  // next link clicked
		if ((maxScroll+origin) > 720) {
			var dist = Math.ceil((xpos - (origin+final_x))/10);
			xpos = xpos - dist;
		}
  }	
  elem.style.left = xpos + "px";
  var repeat = "moveElement('"+elementID+"',"+final_x+","+interval+")";
  elem.movement = setTimeout(repeat,interval);
}

function prepareGallery() { 
	if (!document.getElementsByTagName) return false;
	if (!document.getElementById) return false;
	if (!document.getElementById("discoveries_gallery")) return false;
	var elem = document.getElementById("discoveries_gallery");
	var elemChildren = elem.childNodes.length;
	var next = document.getElementById("discoveries_next")
 	next.onclick = function() {
		moveElement("discoveries_gallery",-630,10);
		return false;
	}
	var prev = document.getElementById("discoveries_prev")
	prev.onclick = function() {
		moveElement("discoveries_gallery",630,10);
		return false;
	}
}

function prepareDiscovery() {
	var tgallery = document.getElementById("discoveries_gallery");
	var thumbnail = tgallery.getElementsByTagName("a");
	for (var i=0; i<thumbnail.length; i++) {
		lnk = thumbnail[i].getAttribute("href");
	}
}


addLoadEvent(prepareGallery);
addLoadEvent(prepareDiscovery);


/* helpers */

function toggleOnClass(me) {
	var dgelemChildren = document.getElementById("discoveries_gallery").getElementsByTagName("a");
	for (var elem in dgelemChildren) {
		dgelemChildren[elem].className = "off";
	}
	me.className='on';
}