link-transition-before.html

Enable keyboard shortcuts

<!DOCTYPE HTML>

<html class="reftest-wait">

<style type="text/css">

a {

  border-bottom: 1px solid transparent;

  transition: all 2s linear;

a.start {

  border-bottom: 1px solid #000000;

/* Can be anything, just need to ensure pseudos cascade */

:before {

  color: blue;

</style>

<a href="http://www.example.com/">example</a>

<script>

let a0 = document.querySelectorAll("a")[0];

a0.classList.add("start");

setTimeout(() => {

  a0.classList.remove("start");

  setTimeout(() => {

    a0.classList.add("start");

    document.documentElement.removeAttribute("class");

  }, 0);

}, 0);

</script>