// Initialize the main navigation tag menus
function initialize_nav() {
	$('header_nav').select('.nav_item').each(function(e) {
		//Position the menu
		submenu = e.down('.subnav_menu');
		submenu.style.width = (150*submenu.select('ul').size())+'px';
		// submenu.style.left = '-'+((submenu.getWidth()-e.getWidth())/2)+'px'; //Center the menu
		//Show menu on mouseover
		e.observe('mouseover', function(event) {
			e.addClassName('selected');
			e.down('div').show();
		});
		//Hide menu on mouseout
		e.observe('mouseout', function(event) {
			e.removeClassName('selected');
			e.down('div').hide();
		})
	});
}