window.onloadListeners = new Array();
addOnLoadListener(getNaviElements);

// Adding onload calls
function addOnLoadListener(listener){
	window.onloadListeners[window.onloadListeners.length] = listener;
}

// Running onload calls
window.onload=function(){
	for(var i=0; i<window.onloadListeners.length;i++){
		var func=window.onloadListeners[i];
		func.call();
	}
}

// Details for eventloader
var BUTTON_CLASSNAME = new Array();
BUTTON_CLASSNAME[0] = "button";
BUTTON_CLASSNAME[1] = "buttonClicked";

var BUTTON_ELEMENT_TYPE = "div";

var MENU_AREA_ID_PREFIX = "nav_";
var ELEMENT_HIDE_CLASSNAME = "hide";
var ELEMENT_SHOW_CLASSNAME = "show";
var ELEMENT_BUTTON_CLASSNAME = "button";
var ELEMENT_CLICKEDBUTTON_CLASSNAME = "buttonClicked";


// Adding onclick listeners for divs
function getNaviElements(){
	var candidates = document.getElementsByTagName(BUTTON_ELEMENT_TYPE);
	
	if(candidates) {
	
		for(var i=0; i<candidates.length; i++){
			var candidate = candidates[i];

				if(candidate.className==BUTTON_CLASSNAME[0] || candidate.className==BUTTON_CLASSNAME[1]){
					candidate.onclick = displayHide;
				}
		}
	}
}

// Display / hide menu element
function displayHide(){
	
	// Button ID format: 10_navbutton
	var buttonID = parseInt(this.id);
		
	var node = document.getElementById(MENU_AREA_ID_PREFIX+buttonID);

	// Slide up
	if (this.className != ELEMENT_BUTTON_CLASSNAME) {
		Effect.BlindUp(node, {duration: 0.2});
		this.className = ELEMENT_BUTTON_CLASSNAME;

	} else {
		// Slide down
		Effect.BlindDown(node, {duration: 0.2});
		this.className = ELEMENT_CLICKEDBUTTON_CLASSNAME;
	}

}