web-animations/responsive/offsetDistance.html

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id='container'>
    <div id='element'></div>
</div>
<script>

var container = document.getElementById('container');
var element = document.getElementById('element');

test(function() {
    var keyframes = [
        {offsetDistance: '4%'},
        {offsetDistance: '12%'}
    ];

    element.style.width = '100';
    element.style.height = '200';
    var player = element.animate(keyframes, 20);
    player.pause();
    player.currentTime = 15;
    element.style.width = '300';
    element.style.height = '600';
    assert_equals(getComputedStyle(element).offsetDistance, '10%');
}, 'offsetDistance percentages are supported');

test(function() {
    var keyframes = [
        {offsetDistance: '8em'},
        {offsetDistance: '16em'}
    ];

    element.style.fontSize = '10px';
    var player = element.animate(keyframes, 20);
    player.pause();
    player.currentTime = 5;
    element.style.fontSize = '20px';
    assert_equals(getComputedStyle(element).offsetDistance, '200px');
}, 'offsetDistance lengths respond to style changes');

test(function() {
    var keyframes = [
        {offsetDistance: 'inherit'},
        {offsetDistance: '200px'}
    ];

    container.style.offsetDistance = '100px';
    var player = element.animate(keyframes, 10);

    player.pause();
    player.currentTime = 5;

    container.style.offsetDistance = '400px';
    assert_equals(getComputedStyle(element).offsetDistance, '300px');
}, 'offsetDistance responsive to inherited offsetDistance changes');
</script>