function init(){
	$$('ul#main_nav li ul').each(
		function(SubList) {
			Element.hide(SubList);
			Element.addClassName(SubList, "subLevel");
		});
	
	if($('imageRotate'))
		imageRotate();
			
	$('main_nav').insert({before:'<div id="cover"></div>'});
	document.observe('mouseover', showSubLevel);
	document.observe('mouseout', hideSubLevel);
}

function showSubLevel(event) {
	event.stop();
	var element = Event.element(event);
	var ul = element.down('ul');
	if(element.down('ul') && element.down('ul').hasClassName('subLevel')){
		$$('ul#main_nav li ul').invoke('hide');
		element.down('ul').show();
		$('cover').show();
	}
	if(element.tagName == 'BODY' || element.tagName == 'HTML' || element == $('cover')){
		$$('ul#main_nav li ul').invoke('hide');
		$('cover').hide();
	}
}

function hideSubLevel(event) {
	event.stop();
	var element = Event.element(event);
	var nav = $('main_nav');
	if(element.up('ul')) {
		if(element.up('ul') == nav || element.up('ul').hasClassName('subLevel'))
			$continue;
		else {
			$$('ul#main_nav li ul').invoke('hide');
			$('cover').hide();
		}
	} else {
		$$('ul#main_nav li ul').invoke('hide');
		$('cover').hide();
	}
}

function imageRotate() {
	var bgimage = [];
	bgimage[0] = "../images/header-image_1-trans.png";
	bgimage[1] = "../images/header-image_2-trans.png";
	bgimage[2] = "../images/header-image_3-trans.png";
	bgimage[3] = "../images/header-image_4-trans.png";
	var index = Math.floor(Math.random() * bgimage.length);
	$('imageRotate').replace("<img id='imageRotate' src='" + bgimage[index] + "'></img>");
}

document.observe('dom:loaded', init);