<!DOCTYPE html>
<html>
<head>
    <style>
        #box {
            height: 100px;
            width: 100px;
            background-color: blue;
            animation: move 1 1s linear;
        }
        
        @keyframes move {
            from { transform: translate(0, 0); }
            50%  { transform: translate(100px, 0); }
            to   { transform: translate(300px, 0); }
        }
    </style>
    <script>
        if (window.testRunner) {
            testRunner.dumpAsText();
            testRunner.waitUntilDone();
        }

        window.addEventListener('load', () => {
            let box = document.getElementById('box');
            box.addEventListener('animationstart', () => {
                if (window.testRunner)
                    testRunner.notifyDone();
            });
        }, false);
    </script>
</head>
<body>
    <p>This test should not crash.</p>
    <div id="box"></div>
</body>
</html>