var timeout         = 500;
var closetimer		= 0;
var ddmenuitem      = 0;

function main_menu_open() {
	main_menu_canceltimer();
	main_menu_close();
	ddmenuitem = $(this).find('ul').eq(0).css('visibility', 'visible');
}

function main_menu_close() {
    if(ddmenuitem) ddmenuitem.css('visibility', 'hidden');
}

function main_menu_timer() {
	  closetimer = window.setTimeout(main_menu_close, timeout);
}

function main_menu_canceltimer() {
	  if(closetimer) {
	      window.clearTimeout(closetimer);
		    closetimer = null;
	  }
}

$(document).ready(function() {
	$('#main_menu > li').bind('mouseover', main_menu_open);
	$('#main_menu > li').bind('mouseout',  main_menu_timer);
});

document.onclick = main_menu_close;