$(document).ready(function() {
	
	$('#navigation li.mainmenu').mouseover(function()
	{
		currentSelected = $('#navigation li.mainmenu.selected');
		elementId = currentSelected.attr('id') + '_sub';
		$('#' + elementId).hide();
		currentSelected.removeClass('selected');
		
		$(this).addClass('selected');
		elementId = $(this).attr('id') + '_sub';
		$('#' + elementId).show();
	});
	
});