This is kinda amazing that this Works : JS in CSS

idonteven.css

#emptyDiv:after {
  content: 'alert("you gotta be kidding me")';
}

index.html

<div id="emptyDiv"></div>

wat.js

eval(eval(window.getComputedStyle(
	document.querySelector('#emptyDiv'), ':after'
).getPropertyValue('content')));