<html>
<head>
    <script>
        function performTest()
        {
            try {
                top.location = "navigation-changed-iframe.html";
            } catch(e) {
                top.postMessage("BLOCKED", "*");
            }
        }
    </script>
</head>
<body onload="performTest();">
    <p>This doc tried to navigate the top page when loaded, which should fail since it's not trigged by user activation while in a sandboxed frame with 'allow-top-navigtaion-by-user-activation'. <br> <br>
    Click the button below, the top navigation should succeed with a new page saying "PASSED: Navigation succeeded." in browsers supporting the 'allow-top-navigtaion-by-user-activation' iframe@sandbox keyword (eg., Chrome v58+); Otherwise, the top navigation should fail.
    </p>
    <button id="b" onclick="performTest();">Navigate the top page</button>
</body>
</html>
