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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /css/css-transitions/animations/change-duration-during-transition.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>transition duration change</title>
<style>
#box {
position: absolute;
height: 100px;
width: 100px;
left: 0px;
background-color: blue;
transition-duration: 1s;
transition-delay: -0.75s;
transition-timing-function: linear;
transition-property: left;
}
</style>
</head>
<body>
<div id="box"></div>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/css/css-transitions/support/helper.js"></script>
<script>
'use strict';
window.onload = () => {
promise_test(async t => {
// Make sure we have rendered the page before making the style change
// to ensure we get transitions.
await waitForAnimationFrames(2);
box.style.left = '400px';
assert_equals(
getComputedStyle(box).left, '300px',
'The transition progresses 75% immediately due to negative ' +
'transition-delay');
box.style.transitionDuration = '7.5s';
assert_equals(
getComputedStyle(box).left, '300px',
'Changing the duration does not affect the current transition');
const anim = document.getAnimations()[0];
anim.finish();
assert_equals(
getComputedStyle(box).left, '400px',
'The final value has been reached when finished');
box.style.left = '1400px';
assert_equals(
getComputedStyle(box).left, '500px',
'With the new duration taking effect, the transition progresses ' +
'10% immediately');
}, 'Transition duration change should not affect transition in progress');
};
</script>
</body>
</html>