function dropdown_setup_hover_event( element, duration, listener ) {
	return new HoverEvent( element, duration, function() { listener.show( element ); } );
}

function dropdown_set_timeout( listener ) {
	return window.setTimeout( function() { listener.hide( listener.active, true ); }, listener.timeoutduration );
}

function dropdown_setup_timeout_events( listener ) {
	Event.observe( $(listener.active+"-dropdown"), "mouseout", function(event) { listener.startTimeout(); } );
	Event.observe( $(listener.active+"-dropdown"), "mouseover", function(event) { listener.stopTimeout(); } );
	Event.observe( $(listener.active), "mouseover", function(event) { listener.stopTimeout(); } );	
	Event.observe( $(listener.active), "mouseout", function(event) { listener.startTimeout(); } );	
}

function dropdown_remove_timeout_events( listener ) {
	Event.stopObserving( $(listener.active+"-dropdown"), "mouseout", function(event) { listener.startTimeout(); } );
	Event.stopObserving( $(listener.active+"-dropdown"), "mouseover", function(event) { listener.stopTimeout(); } );
	Event.stopObserving( $(listener.active), "mouseover", function(event) { listener.stopTimeout(); } );
}

function dropdown_showmenu( element ) {
  id = element.parentNode.id;
	if (this.active == id) return;
	
	if (this.active != null) this.hide( this.active, false );
	this.active = id;
	
	var button = $(id);
	var menu = $(id+"-dropdown");
	
	menu.style.zIndex="200";
	menu.setOpacity(1.0);
	menu.style.left = (Position.cumulativeOffset(button)[0] + this.offsetx) + "px";
	menu.style.top = (Position.cumulativeOffset(button)[1] + this.offsety) + "px";
	menu.style.display='block';
	
	dropdown_setup_timeout_events( this );
	
	Element.addClassName(button, button.id+"-active");
}

function dropdown_hidemenu( id, grace ) {
	var button = $(id);
	var menu = $(id+"-dropdown");
	
	if (grace) {
		new Effect.Fade( menu, {duration: 0.25} );
	} else {
		menu.hide();
	}
	
	dropdown_remove_timeout_events( this );
	
	Element.removeClassName( button, button.id+"-active" );
	
	if (this.active == id) this.active = null;
}

function dropdown_timeout_start() {
	if (this.timeout != null) return;
	this.timeout = dropdown_set_timeout( this );
}

function dropdown_timeout_stop() {
	if (this.timeout != null) window.clearTimeout(this.timeout);
	this.timeout = null;
}

function DropDown( element, duration, offsetx, offsety ) {
	this.element = $(element);
	this.duration = duration;
	this.offsetx = offsetx;
	this.offsety = offsety;
	
	this.show = dropdown_showmenu;
	this.hide = dropdown_hidemenu;
	
	this.active = null;
	
	this.timeout = null;
	this.timeoutduration = 1000;
	this.startTimeout = dropdown_timeout_start;
	this.stopTimeout = dropdown_timeout_stop;
	
	var anchors = this.element.getElementsByTagName("A");
	for (var i=0; i<anchors.length; i++) {
		if (Element.hasClassName(anchors[i], "dropdown-link")) {
			dropdown_setup_hover_event( anchors[i], this.duration, this );
		}
	}
}