window.addEvent('domready', function() {
 
 	// navigation //
  	$('main_navigation_about').addEvents({
		'mouseenter': function() { $('main_navigation_about_black_bar').setStyle('display', 'block'); },
		'mouseleave': function() { $('main_navigation_about_black_bar').setStyle('display', 'none'); }
	});
	
	/*
	$('main_navigation_work').addEvents({
		'mouseenter': function() { $('main_navigation_work_black_bar').setStyle('display', 'block'); },
		'mouseleave': function() { $('main_navigation_work_black_bar').setStyle('display', 'none'); }
	});
	
*/
		
	$('main_navigation_contact').addEvents({
		'mouseenter': function() { $('main_navigation_contact_black_bar').setStyle('display', 'block'); },
		'mouseleave': function() { $('main_navigation_contact_black_bar').setStyle('display', 'none'); }
	});
	
	$('main_navigation_clients').addEvents({
		'mouseenter': function() { $('main_navigation_clients_black_bar').setStyle('display', 'block'); },
		'mouseleave': function() { $('main_navigation_clients_black_bar').setStyle('display', 'none'); }
	});
});