gecko/dom/ipc/test.xul

<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
        width="800" height="800" orient="vertical">
  <script>
    function restart() {
      var y = document.getElementById('page');
      var p = y.parentNode;
      p.removeChild(y);
      p.appendChild(y);
    }
    
    function loadURL(url) {
      document.getElementById('page').setAttribute('src', url);
    }

    function randomClick() {
       // First focus the remote frame, then dispatch click. This way remote frame gets focus before
       // mouse event.
       document.getElementById('page').QueryInterface(Components.interfaces.nsIFrameLoaderOwner)
                                      .frameLoader.activateRemoteFrame();
       var frameLoader = document.getElementById('page').QueryInterface(Components.interfaces.nsIFrameLoaderOwner).frameLoader;
       var x = parseInt(Math.random() * 100);
       var y = parseInt(Math.random() * 100);
       frameLoader.sendCrossProcessMouseEvent("mousedown", x, y, 0, 1, 0, false);
       frameLoader.sendCrossProcessMouseEvent("mouseup", x, y, 0, 1, 0, false);
     }
  </script>

  <toolbar id="controls">
    <toolbarbutton label="Back"/>
    <toolbarbutton label="Forward"/>
    <textbox onchange="loadURL(this.value)" flex="1" id="URL"/>
    <toolbarbutton onclick="restart()" label="Recover"/>
    <toolbarbutton onclick="randomClick()" label="random click"/>
  </toolbar>

  <browser type="content" src="http://www.google.com/" flex="1" id="page" remote="true"
           onfocus="this.QueryInterface(Components.interfaces.nsIFrameLoaderOwner).frameLoader.activateRemoteFrame();"/>
</window>