Slide + fade effect using CSS transitions

Problem

I'm trying to replicate this effect using CSS effects or transitions.

Using animations I can animate the opacity, but only fadeIn, and the height (which should control the slide) doesn't seem to work at all :(

The closest I've got is by using javascript to set a temporary class on the element I want to animate, and on which I apply the initial opacity. But height doesn't work either. And there seems to be a slight delay on animation start.

Any other ideas?


So I ended up using the solution posted in the question Simon mentioned: With javascript I wrap the element I want to animate within a "wrapper" DIV on which I apply the animation. The wrapper will get its height changed from 0 to the height of the content DIV every time the label is clicked:

fiddle here

I know it requires some javascript, but the idea is to make the animation in CSS, and this is what it does. And if JS is disabled, the toggle will still work...

Problem courtesy of: nice ass

Solution

You can't currently animate on height when one of the heights involved is auto, you have to set two explicit heights. There's an extensive workaround posted as an answer to this similar question.

Solution courtesy of: Simon Pertersen

Discussion

I made an alteration to your JS Fiddle, I beleive this is what you want; please see it here.

You need to specify a height on the div originally (0) and don't forget overflow:hidden; so that the content doesn't 'spil out' of the div. You will still need jQuery / Javascript however, to toggle a class but it means much less Javascript is required. (I toggled the class "change" which you will see on that fiddle)

input {
   display:none;
}
label {
    display:inline-block;
}
div {
    white-space: pre;
    background: #eee;
    color: #333;
    overflow:hidden;
    height:0;
    opacity:0;
    -moz-transition:height 1s opacity 1s;
    -webkit-transition:height 1s opacity 1s;
    -o-transition:height 1s opacity 1s;
    -ms-transition:height 1s opacity 1s;
    transition:height 1s, opacity 1s;
}
.changed {
    height:200px;
    opacity: 1;
}

I added a few vendor prefixes to the transition CSS propery as I'm not sure what browser you'll be using and I'm on firefox so I need the -moz- prefix lol :)

The only problem I can see with this is that height:auto or height:100% doesn't animate, so you'll need to specify ems or px... If this is going to be a problem (like if the content will be dynamic), I would advise using jQuery for the height animation.

Discussion courtesy of: Dan

This recipe can be found in it's original form on Stack Over Flow.