<!doctype html> <meta charset="utf-8"> <link rel="help" href="https://drafts.csswg.org/css-transitions/#starting"> <link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1461070"> <link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <style> #t { color: red; transition-property: color, color; transition-duration: 1s, 0s; } </style> <div id="t"></div> <script> test(function() { let div = document.getElementById("t"); assert_equals(getComputedStyle(div).color, "rgb(255, 0, 0)"); div.style.color = "green"; assert_equals( div.getAnimations().length, 0, "No transition should've started" ); assert_equals(getComputedStyle(div).color, "rgb(0, 128, 0)"); }, "transition-duration of 0 prevents earlier transitions with the same property from starting."); </script>