Animation CSS3: display + opacity

Question

I have got a problem with a CSS3 animation.

.child {
    opacity: 0;
    display: none;

    -webkit-transition: opacity 0.5s ease-in-out;
    -moz-transition: opacity 0.5s ease-in-out;
    transition: opacity 0.5s ease-in-out;
}

.parent:hover .child {
    opacity: 0.9;
    display: block;
}

This code only works if I remove the change of display.

I want to change the display just after the hover but the opacity should be changed using the transition.

Answer 1

I changed a bit but the result is beautiful.

.child {
    width: 0px;
    height: 0px;
    opacity: 0;
}

.parent:hover child {
    width: 150px;
    height: 300px;
    opacity: .9;
}

Thank you to everyone.

Answer 2

Based on Michaels answer this is the actual CSS code to use

.parent:hover .child
{
    display: block;

    -webkit-animation: fadeInFromNone 0.5s ease-out;
    -moz-animation: fadeInFromNone 0.5s ease-out;
    -o-animation: fadeInFromNone 0.5s ease-out;
    animation: fadeInFromNone 0.5s ease-out;
}

@-webkit-keyframes fadeInFromNone {
    0% {
        display: none;
        opacity: 0;
    }

    1% {
        display: block;
        opacity: 0;
    }

    100% {
        display: block;
        opacity: 1;
    }
}

@-moz-keyframes fadeInFromNone {
    0% {
        display: none;
        opacity: 0;
    }

    1% {
        display: block;
        opacity: 0;
    }

    100% {
        display: block;
        opacity: 1;
    }
}

@-o-keyframes fadeInFromNone {
    0% {
        display: none;
        opacity: 0;
    }

    1% {
        display: block;
        opacity: 0;
    }

    100% {
        display: block;
        opacity: 1;
    }
}

@keyframes fadeInFromNone {
    0% {
        display: none;
        opacity: 0;
    }

    1% {
        display: block;
        opacity: 0;
    }

    100% {
        display: block;
        opacity: 1;
    }
}

Answer 3

I had the same problem. I tried using animations instead of transitions - as suggested by @MichaelMullany and @Chris - but it only worked for webkit browsers even if I copy-pasted with "-moz" and "-o" prefixes.

I was able to get around the problem by using visibility instead of display. This works for me because my child element is position: absolute, so document flow isn't being affected. It might work for others too.

This is what the original code would look like using my solution:

.child {
    position: absolute;
    opacity: 0;
    visibility: hidden;

    -webkit-transition: opacity 0.5s ease-in-out;
    -moz-transition: opacity 0.5s ease-in-out;
    transition: opacity 0.5s ease-in-out;
}

.parent:hover .child {
    position: relative;
    opacity: 0.9;
    visibility: visible;
}

Answer 4

If possible - use visibility instead of display

For instance:

.child {
    visibility: hidden;
    opacity: 0;
    transition: opacity 0.3s, visibility 0.3s;
}

.parent:hover .child {
    visibility: visible;
    opacity: 1;
    transition: opacity 0.3s, visibility 0.3s;
}

Answer 5

One thing that I did was set the initial state's margin to be something like "margin-left: -9999px" so it does not appear on the screen, and then reset "margin-left: 0" on the hover state. Keep it "display: block" in that case. Did the trick for me :)

Edit: Save the state and not revert to previous hover state? Ok here we need JS:

<style>
.hovered { 
    /* hover styles here */
}
</style>

<script type="text/javascript">
$('.link').hover(function() {
   var $link = $(this);
   if (!$link.hasclass('hovered')) { // check to see if the class was already given
        $(this).addClass('hovered');
   } 
});
</script>

Answer 6

If you are triggering the change with JS, let's say on click, there is a nice workaround.

You see the problem happens because the animation is ignored on display:none element but browser applies all the changes at once and the element is never display:block while not animated at the same time.

The trick is to ask the browser to render the frame after changing the visibility but before triggering the animation.

Here is a JQuery example:

    $('.child').css({"display":"block"});
    //now ask the browser what is the value of the display property
    $('.child').css("display"); //this will trigger the browser to apply the change. this costs one frame render
    //now a change to opacity will trigger the animation
    $('.child').css("opacity":100);