function posMouse(e){
 var mouX = 0, mouY = 0;
 if (!e) e = window.event;
 if (e.pageX || e.pageY) {
  mouX = e.pageX;
  mouY = e.pageY;
 } else if (e.clientX || e.clientY) {
  mouX = e.clientX + (document.documentElement.scrollLeft || document.body.scrollLeft) - document.documentElement.clientLeft;
  mouY = e.clientY + (document.documentElement.scrollTop || document.body.scrollTop) - document.documentElement.clientTop;
 }
 return {"x":mouX, "y":mouY}
}

$(document).ready(function(){
 $('#menu_3_head').mouseover(function(){
  $('#box').slideDown('slow');
 })
 .mouseleave(function(e){
  var elem = $('#box'), mou = posMouse(e);
  if ((mou.x < elem.offset().left) || (mou.x > elem.offset().left + elem.width()) || (mou.y < elem.offset().top))
   elem.slideUp('slow');
 });
 $('#box').mouseleave(function(){
  $(this).slideUp('slow');
 });
});