<!doctype html> <title>An animation of an attribute ('class') does not change the DOM attribute value</title> <link rel="help" href="https://www.w3.org/TR/2001/REC-smil-animation-20010904/#BasicAnim"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <style> .animated { fill: blue; } </style> <svg> <rect class="base"> <set attributeName="class" to="animated"/> </rect> <rect> <set attributeName="class" to="animated"/> </rect> </svg> <script> async_test(t => { onload = t.step_func(() => { requestAnimationFrame(t.step_func_done(() => { let rects = document.getElementsByTagName('rect'); assert_true(rects[0].hasAttribute('class')); assert_equals(rects[0].getAttribute('class'), 'base'); assert_equals(getComputedStyle(rects[0]).getPropertyValue('fill'), 'rgb(0, 0, 255)'); assert_false(rects[1].hasAttribute('class')); assert_equals(rects[1].getAttribute('class'), null); assert_equals(getComputedStyle(rects[0]).getPropertyValue('fill'), 'rgb(0, 0, 255)'); })); }); }); </script>