window-top-null.html

Enable keyboard shortcuts

This WPT test may be referenced by the following Test IDs:
- /html/browsers/windows/nested-browsing-contexts/window-top-null.html - WPT Dashboard Interop Dashboard

<!doctype html>

<meta charset="utf-8">

<title>window.top: `null`</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<div id="log"></div>

<script>

async_test(function (t) {

  var iframe = document.createElement('iframe');

  iframe.onload  = t.step_func_done(() => {

    var iWindow = iframe.contentWindow;

/**

     * `top` should return the top-level browsing context but will return

     * `null` if none exists, such as when any of the BC's ancestor browsing

     *  context container's document elements are disconnected/removed.

*/

    assert_equals(iWindow.top, window);

    document.body.removeChild(iframe);

    assert_equals(iWindow.top, null);

});

  document.body.appendChild(iframe);

}, '`window.top` is null when browsing context container element removed');

async_test(t => {

  var iframe = document.createElement('iframe');

  var iframe2, removedEl;

  var testFunc = t.step_func(() => {

    var frameWindow = iframe.contentWindow;

    var frame2Window = iframe2.contentWindow;

    assert_equals(frameWindow.top, window);

    assert_equals(frame2Window.top, window);

    iframe.removeEventListener('load', nestFrame);

    iframe2.removeEventListener('load', testFunc);

    removedEl = document.body.removeChild(iframe);

    assert_equals(frameWindow.top, null);

    assert_equals(frame2Window.top, null);

    removedEl.addEventListener('load', t.step_func_done(() => {

      // reattached iframe's browsing context will report window.top

      assert_equals(removedEl.contentWindow.top, window);

      // removed/re-added iframes will have new browsing context / window

      assert_equals(frameWindow.top, null);

      assert_equals(frame2Window.top, null);

    }));

    document.body.appendChild(removedEl);

});

  var nestFrame = function () {

    iframe2 = iframe.contentDocument.createElement('iframe');

    // Workaround for https://bugzilla.mozilla.org/show_bug.cgi?id=1229707

    iframe2.src = '/common/blank.html';

    iframe2.addEventListener('load', testFunc);

    iframe.contentDocument.body.appendChild(iframe2);

};

  iframe.addEventListener('load', nestFrame);

  document.body.appendChild(iframe);

}, '`window.top`null when any ancestor browsing context container removed');

</script>