Can I apply a CSS transition to the overflow property? - css

Question

I'm trying to set a transition-delay to the overflow property of body when a div is clicked by adding a class to the body as follows:
$("div").click(function(){
$("body").addClass("no_overflow");
});
div{
background:lime;
height:2000px;
}
.no_overflow{
overflow:hidden;
}
body{
overflow:auto;
transition: overflow 0 2s;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>I'm div</div>
However, this doesn't seem to work (there's no delay). Am I doing anything wrong here?
I know this can be achieved by using setTimeout function, but was wondering why can't this be achieved using css transitions? Are there any specific style properties to which css transitions can be applied?

Answer 1

There are many properties that can't be transitioned. overflow is among them; the render engine has no idea how to transition between "hidden" and "shown", because those are binary options, not intervals. This is the same reason why you can't transition between display: none; and display: block; (for example): there are no in-between phases to use as transitions.
You can see a list of properties you can animate here on Mozilla Developer Network.

Answer 2

You can simulate a delay with animation:
$("div").click(function() {
$("body").addClass("no_overflow");
});
div {
background: lime;
height: 2000px;
}
.no_overflow {
overflow: hidden;
/* persist overflow value from animation */
animation: 7s delay-overflow;
}
body {
overflow: auto;
}
#keyframes delay-overflow {
from { overflow: auto; }
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>I'm div</div>
You'll have to apply a separate animation to .body if you want a delay on removeClass, and also to take care that the two animations don't overlap or they'll cancel each other out.

Answer 3

overflow isn't CSS animatable property. You can see full list of animatable CSS properties there.

Answer 4

In case someone is looking at the answer, like I was, for a way to animate the cropping of an element which requires overflowing - here is the solution that worked for me: the clip-path css property which is animatable and very versatile.
Here is a cool tool to play around with, in order to get the proper start / end values for an animation: https://bennettfeely.com/clippy/.

Answer 5

Dmitry's answer should be the only accepted answer, as it is a pure CSS solution applying delay to "non-animatable" properties. However it's worth to mention, that the CSS rule applying animation should be "triggerable" each time when it is needed.
For instance, the following code does not work:
#keyframes show-overflow {
from { overflow: hidden; }
}
.hideable, .overlay {
font-size: 36px;
height: 50px;
}
.hideable {
transition: height 2s;
overflow: visible;
animation: show-overflow 2s; /* this line should be in separate "triggerable" CSS rule to work */
}
.hideable.hidden {
height: 0;
overflow: hidden;
}
<button onclick="document.getElementById('hideable').classList.toggle('hidden')">
Clik HERE to hide/show the text below
</button>
<div id='hideable' class='hideable'>
This is the text to hide and show.
</div>
<div class='overlay'>
This is overlaying text
</div>
But after moving the marked property to a separate CSS rule, everything works as expected:
#keyframes show-overflow {
from { overflow: hidden; }
}
.hideable, .overlay {
font-size: 36px;
height: 50px;
}
.hideable {
transition: height 2s;
overflow: visible;
}
.hideable:not(.hidden) {
animation: show-overflow 2s; /* now this works! */
}
.hideable.hidden {
height: 0;
overflow: hidden;
}
<button onclick="document.getElementById('hideable').classList.toggle('hidden')">
Clik HERE to hide/show the text below
</button>
<div id='hideable' class='hideable'>
This is the text to hide and show.
</div>
<div class='overlay'>
This is overlaying text
</div>

Answer 6

It makes sense that you can't transition between binary attributes for example overflow: hidden; and overflow: visible but it would have been really nice if instead of "transitioning" then it would be like (in js pseudo code:
setTimeout("applyOverflowVisible()", transitionTime);
But of course you can do this yourself in JavaScript but then you are splitting the code between places and it can make it difficult to understand by someone else. I guess using things like React helps but even there I would want to avoid mixing css into the js.