function buttonAction(left)
{
	var el = getElement("ltBtn");
	el.style.display =  left < 0 ? "block" : "none";

	var er = getElement("rtBtn");
	er.style.display =  (iCount-4) * iWidth + left > 0 ? "block" : "none";	
}

function toRight()
{
	var el = getElement("imgLine");
	var elLeft = parseInt(el.style.marginLeft);
	if ((iCount-4) * iWidth + elLeft > 0) {
		elLeft = elLeft - iWidth;
		el.style.marginLeft = elLeft + "px";
	}
	buttonAction(elLeft);
	return false;
}

function toLeft()
{
	var el = getElement("imgLine");
	var elLeft = parseInt(el.style.marginLeft);
	if (elLeft < 0) {
		elLeft = elLeft + iWidth;	
		el.style.marginLeft = elLeft + "px";
	}
	buttonAction(elLeft);
	return false;
}

function handle(delta) {
  if (delta < 0)
     toRight();
  else
     toLeft();
  return false;
}

function cancelEvent(e) {
   e = e ? e : window.event;
   if(e.stopPropagation)
     e.stopPropagation();
   if(e.preventDefault)
     e.preventDefault();
   e.cancelBubble = false;
   e.cancel = true;
   e.returnValue = false;
   return false;
}

function wheel(event){

  event = event ? event : window.event;
  var delta = 0;
  delta = event.detail ? -event.detail/3 : event.wheelDelta/120;
  if (delta)
    result = handle(delta);
  cancelEvent(event);
}

function hookEvent(element, eventName, callback) {
   if(typeof(element) == "string")
     element = getElement(element);
   if(element == null) {
     return;
   }
   if(element.addEventListener)
   {
     if(eventName == 'mousewheel')
       element.addEventListener('DOMMouseScroll', callback, false);
     element.addEventListener(eventName, callback, false);
   }
   else if(element.attachEvent)
     element.attachEvent("on" + eventName, callback);
 }

window.onload = function () {
hookEvent('scroll', 'mousewheel', wheel);
}