How to create a pop-up without JavaScript

Ever wanted a pop-up mechanism on your website, but you don't want to use JavaScript? Here's how:

  1. Add a <details> and <summary> to your document
  2. Insert a <div> to your <details> element
  3. Add a scaling animation to this <div>
  4. Add this animation to the <div> when the [open] attribute is toggled on the <details> element

Toggle the How it works button for more info.

How it works

The scaling effect you see when you open this <details> element is created by using a keyframe animation. 

@keyframes scale { 
 0% {
  transform: scale(0);
 }
 100% {
  transform: scale(1);
 }
}

This animation is added to the <div> , but only when the [open] attribute is toggled. 

details[open] div { 
 animation: scale .15s ease;
}

Sadly there's no way (that I know of) to animate the <div> when the <details> is closing.