function prepareGallery() {
	if(!document.getElementById("imagegallery"))return false;
	var gallery = document.getElementById("imagegallery");
	var links = gallery.getElementsByTagName("a");
		
		for ( var i=0; i<links.length; i++){
			links[i].onmouseover = links[i].onclick = function(){
			return showPic(this);
		}
	}
}


function showPic(whichpic){
	if(!document.getElementById("placeholder"))return true;
	var source = whichpic.getAttribute("href");
	var placeholder = document.getElementById("placeholder");

	if(placeholder.nodeName != "IMG") return true;
		placeholder.setAttribute("src",source);
	return false;
}



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

addLoadEvent (prepareGallery);