jQuery css Visibility with animation

$('.drop1').css({opacity: 1.0, visibility: "visible"}).animate({opacity: 0}, 200);

why make it so hard, instead of animating the css, you could use the default fade functionality

$('.drop1').fadeIn(200);
$('.drop1').fadeOut(200);

edit

if you however want to fade it out without losing the height . you can use fadeTo(duration, opacity, [callback]);

$('.drop1').fadeTo(200, 0);

check this example: http://jsfiddle.net/ufLwy/1/

I was having similar issues, and here's what I ended up doing.

$.fadeToHidden = function ( selector, duration, complete ) {
    $.when(
        $( selector ).fadeTo( duration, 0 )
    ).done( function(){
        $( selector ).css('visibility', 'hidden')
        complete();
    });
}

The reason I did this is that

1. fadeIn()/fadeOut() uses 'display' which F's up an element's height
2. fadeTo doesn't affect 'visibility', so while the element is visually hidden with opacity:0 users are still able to interact (i.e. click) the invisible element
3. animate() is asynchronous so chaining CSS at the end doesn't guarantee that it will run when the animation is complete. Only by using the Deferred object that animations return ($.when() / $.done()) will you be guaranteed that the css is applied after all animations are complete.

EDIT Alternatively, you could apply to "visibility:hidden" to each individual element once their respective animation is complete. This may be slightly quicker for selecting larger groups of elements, since you're only querying the DOM for the group of elements once.

$.fadeToHidden = function ( selector, duration, complete ) {
    $.when(
        $( selector ).fadeTo( duration, 0 , function(){ 
            $(this).css('visibility', 'hidden');
        } )
    ).done( complete );
}