var position = 0;
function IEcheck(){

	if(isIE){
		var nextbutton = document.getElementById("topimagenext");
		nextbutton.style.visibility = 'hidden';
	}	
}	
function topimagenext(){
	if (!isIE()) {
		var nextbutton = document.getElementById("topimagenext");
		var prevbutton = document.getElementById("topimageprev");
		
		prevbutton.style.visibility = 'visible';
		
		if (position < 4){
			new Effect.Move("topimages", {x:-600,y:0,duration:1.5, queue: 'end'});
			position++;
		}
		if (position == 3) {
			nextbutton.style.visibility = "hidden";
		}
	}
}
function topimageprev(){
	if (!isIE()) {
		var nextbutton = document.getElementById("topimagenext");
		var prevbutton = document.getElementById("topimageprev");
		
		nextbutton.style.visibility = 'visible';
		
		if (position > 0){
			new Effect.Move("topimages", {x:600,y:0,duration:1.5, queue: 'end'});
			position--;
		}
		if (position == 0){
			prevbutton.style.visibility = "hidden";
		}
	}
}
function isIE()
{
  return /msie/i.test(navigator.userAgent) && !/opera/i.test(navigator.userAgent);
}