LibTest/html/IFrameElement/previousElementSibling_A01_t01.dart

// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion final Element previousElementSibling
/// The element immediately preceding the given one in the tree, or null if
/// there is no sibling element.
/// @description Checks expected attribute values.

import "dart:html";
import "../../../Utils/expect.dart";

main() {
  IFrameElement x = new Element.html('<iframe class="y">Content Text</iframe>')
      as IFrameElement;
  Expect.isNull(x.previousElementSibling);

  var body = document.body;
  var child = body?.children.last;
  body?.append(x);
  Expect.equals(child, x.previousElementSibling);
}