I have an element whose width I'd like to animate when its contents change. It has width: auto
, and this never changes. I've seen this trick, but that's for transitioning between two values and one is set. I'm not manipulating the values at all, only the content, and I'd like my element's size to change with animation. Is this at all possible in CSS?
Here's a simplified version of my code:
.myspan {
background-color: #ddd;
}
.myspan:hover::after {
content: "\00a0\f12a";
font-family: Ionicons;
font-size: 80%;
}
<link href="https://code.ionicframework.com/ionicons/2.0.1/css/ionicons.min.css" rel="stylesheet"/>
<html>
<body>
<span class="myspan">Hello!</span>
</body>
</html>
I'd like the changing size to animate when the user hovers over the element.
Updated answer (2024-11)
Now there's a new experimental css function that solve this and allow to animate auto
width: calc-size(auto);
Note: check browser support before using this in production.
Original answer
As I commented, one can't animate auto
(yet), so either use the max-width
/max-height
trick, or, if you need it to be more exact, set the width using a script.
With the max-width
/max-height
trick, give it a value big enough to accommodate the widest.
Stack snippet
.myspan {
display: inline-block;
font-size: 30px;
background-color: #ddd;
vertical-align: bottom;
}
.myspan::after {
content: " \00a0\f12a ";
font-family: ionicons;
font-size: 80%;
display: inline-block;
max-width: 0;
transition: max-width .6s;
vertical-align: bottom;
overflow: hidden;
}
.myspan:hover::after {
max-width: 80px;
transition: max-width 1s;
}
<link href="https://code.ionicframework.com/ionicons/2.0.1/css/ionicons.min.css" rel="stylesheet" />
<span class="myspan">Hello!</span>