<?xml version="1.0"?>

<overlay id="helloworldOverlay"
  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <script type="application/x-javascript"
            src="chrome://helloworld/content/test.js" />

  <toolbox id="navigator-toolbox">
      <toolbarpalette id="BrowserToolbarPalette">
     <toolbarbutton id="test" class="toolbarbutton-1 chromeclass-toolbar-additional"
                 label="test"
            image="chrome://helloworld/skin/mark.png"
                 onclick="test();"/>
      </toolbarpalette>
  </toolbox>

</overlay>