Tag Archives: animation transition bug regression IE10

IE10 Gotcha: Animating Pseudo-Elements on Hover

I came across a question on Stack Overflow today asking about animating pseudo-elements. This is something I have lamented over in the past since it’s been a supported feature in Internet Explorer 10 for a while, but only recently implemented in Chrome version 26. As it turns out, there was a small edge-case surrounding this feature that I had yet to encounter in Internet Explorer 10.

The following code does two things; first it sets the content and transition properties of the ::after pseudo-element for all paragraphs (there’s only one in this demo). Next, in the :hover state (or pseudo-class), it changes the font-size property to 2em. This change will be transitioned over 1 second, per the instruction in the first block.

p::after {
    content: ", World.";
    transition: font-size 1s;
}

p:hover::after {
    font-size: 2em;
}

Although simple and straight forward, this demo (as-is) doesn’t work in Internet Explorer 10. Although IE10 supports :hover on any element, and IE10 supports pseudo-elements, and IE10 supports animating pseudo-elements, it does not support all three, together, out of the box.

If you change your markup from using a paragraph to using an anchor element, the code begins to work. This seems to suggest some type of regression has taken place, causing Internet Explorer 10 behave similar to Internet Explorer 6 where only anchors could be “hovered” — support for :hover on any element was added in version 7.

Upon playing with this a bit, there does appear to be a few work-arounds:

  1. Change your markup
  2. Use sibling combinators in your selector
  3. Buffer a :hover selector on everything

Let’s look at these one at a time.

Change Your Markup

Rather than having a paragraph tag, you could nest a span within the paragraph, or wrap the paragraph in a div. Either way, you’ll be able to modify your selector in such a way so as to break up the :hover and ::after portions. When the user hovers over the outer element, the content of the inner-element’s pseudo-element is changed.

I don’t like this option; it’s far too invasive and demanding.

Use Sibling Combinators in Your Selector

This was an interesting discovery. I found that if you further modify your selector to include consideration for sibling elements, everything is magically repaired. For instance, the following targets our paragraph based on some other sibling paragraph:

p~p:hover::after {
    font-size: 2em;
}

This is interesting; it doesn’t break the connection between :hover and ::after, but it does modify the root of the selector, which somehow causes things to repair themselves.

What I don’t like about this approach is that it requires you to explicitly declare the sibling selector, as well as the element you’re wishing to target. Of course, we could fix this a bit by targeting a class or id, as well as going with a different sibling combinator:

*~.el:hover::after {}

This targets any element with the .el class that is a sibling of any other element. This gets us a little closer, but still, a bit messy. It requires us to modify every single selector that is part of a pseudo-element animation.

Buffering the :hover Selector

Provided with the question on Stack Overflow was one solution to the problem. As it turns out, if you provide an empty set of rules for the hover state, this fixes all subsequent attempts to animate pseudo-element properties. What this looks like follows:

p:hover {}

p::after {
    content: ", World.";
    transition: font-size 1s;
}

p:hover::after {
    font-size: 2em;
}

Oddly enough, this small addition does indeed resolve the issue. Given the nature of CSS, you can even drop the p portion, and just go with the following fixing it for all elements:

:hover{}

This too results in a functioning Internet Explorer 10 when it comes to animating pseudo-element properties.

Experiment: http://jsfiddle.net/jonathansampson/N4kf9/