chromium/chrome/test/data/extensions/api_test/webrequest/unload/load_frame.js

// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

var frameUrl = decodeURIComponent(location.search.slice(1));
console.assert(frameUrl, 'Frame URL must be specified after "?".');

window.onload = function() {
  var f = document.createElement('iframe');
  f.src = frameUrl;
  document.body.appendChild(f);
};