Transitions on the display: property

You can concatenate two transitions or more, and visibility is what comes handy this time.

div > ul {
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s, opacity 0.5s linear;
}
div:hover > ul {
  visibility: visible;
  opacity: 1;
}

(Don't forget the vendor prefixes to the transition property!)

More details are in this article

• answered 8 years ago
• Sunny Solu

You need to hide the element by other means in order to get this to work. I had the same issue on thispage.

I accomplished the effect by positioning both <div>s absolutely and setting the hidden one to opacity: 0.

If you even toggle the display property from none to block, Your transition on other elements will not occur.

To work around this, always allow the element to be display: block, but hide the element by adjusting any of these means:

1. Set the height to 0.
2. Set the opacity to 0.
3. Position the element outside of the frame of another element that has overflow: hidden.

There are likely more solutions, but you cannot perform a transition if you toggle the element to display: none. For example, you may attempt to try something like this:

div {
    display: none;
    transition: opacity 1s ease-out;
    opacity: 0; 
}

div.active {
    opacity: 1;
    display: block;
}

But that will not work. From my experience, I have found this to do nothing :-(

Because of this, you will always need to keep the element display: block - but you could get around it by doing something like this:

div {
    transition: opacity 1s ease-out;
    opacity: 0; 
    height: 0;
    overflow: hidden;
}

div.active {
    opacity: 1;
    height: auto;
}

• answered 8 years ago
• G John