// adds a function to the page onload, so we don't overwrite existing onload functions
function addOnLoad(f) {
    var currentOnLoad = window.onload;
    if (typeof window.onload != "function") {
        window.onload = f;
    } else {
        window.onload = function() {
            currentOnLoad();
            f();
        }
    }
}

// applys rollovers to tags within element
function addRollOver(node,path,anchor,pulldown){
	node.pulldown = pulldown;

	node.origsrc = path+anchor.id+".gif";
	node.rolloversrc = path+anchor.id+"_a.gif";

	node.anchor = anchor;
	if(typeof rolloverPreloader != "object"){
		rolloverPreloader = new Object();
	};
	rolloverPreloader[node.id+"preload"] = new Image();
	rolloverPreloader[node.id+"preload"].src = node.rolloversrc;
	node.onmouseover = function(){
		clearTimeout(this.to);
		this.pulldown.style.display = "block";
//		alert(this.anchor + " : " + this.rolloversrc);
		this.anchor.style.backgroundImage = "url('"+this.rolloversrc+"')";
		
	}
	node.onmouseout = function(){
		var self = this;
		this.to = window.setTimeout(
			function(){
				self.pulldown.style.display = "none";
				self.anchor.style.backgroundImage =  "url('"+self.origsrc+"')";
			},
			200
		);
	}

}

function assignRollOvers(elementid,directory){
	if(document.getElementsByTagName && document.getElementById){
		var element = document.getElementById(elementid);
	

		// make list of pulldowns... 
		var pulldownlist = element.getElementsByTagName("div");
		var pulldowns = new Array();
		var j=0;
		for(var i=0;i<pulldownlist.length;i++){
			var node = pulldownlist[i];
			if(node.className == "pulldown"){
				pulldowns[j] = node;
				j++;
			}
		}
		
		//make list of anchors
		var anchorslist = element.getElementsByTagName("a");
		var anchors = new Array();
		var j=0;
		for(var i=0; i<anchorslist.length; i++){
			var node = anchorslist[i];
			if(node.className == "navlink"){
				anchors[j] = node;
				j++;
			}	
		}
		
		//make list of toplevel lis
		var lilist = element.getElementsByTagName("li");
		var lis = new Array();
		var j=0;
		for(var i = 0;i<lilist.length;i++){
			var node = lilist[i];
			if(node.className == "navitem"){
				addRollOver(node,directory,anchors[j],pulldowns[j]);
				j++;
			}
		}
	}
	
}

window.onload = function(){
	assignRollOvers('nav2','_media/global/tnav/');
}

// FROM PROTOTYPE.JS
function $() {
  var elements = new Array();

  for (var i = 0; i < arguments.length; i++) {
    var element = arguments[i];
    if (typeof element == 'string')
      element = document.getElementById(element);

    if (arguments.length == 1)
      return element;

    elements.push(element);
  }

  return elements;
}