$(document).ready(function(){

	$("ul.dropdown li").dropdown();

});

$.fn.dropdown = function() {

	$(this).hover(function(){
		$(this).addClass("hover");
		$('> .dir',this).addClass("open");
		$('ul:first',this).css('visibility', 'visible');
           

curPos = $('ul:first',this).offset();
     curTop = curPos.top;
     curHeight = $('ul:first',this).height();
     total_height = curTop + curHeight;
     screenHeight = $(window).height();
scrollTop = $(window).scrollTop();
total_screen = screenHeight + scrollTop;
    if(total_height > total_screen)
{
temp = curHeight - 40;
$('ul:first',this).animate({
     top: '-='+temp
  }, 5, function() {
    // Animation complete.
  });
}

  
	},function(){
		$(this).removeClass("hover");
		$('.open',this).removeClass("open");
		$('ul:first',this).css('visibility', 'hidden');
isOnScreen($('ul:first',this));
	});

}