[nerv_]

выглядит многообещающе

<element name="my-megabutton" extends="button" constructor="MegaButton">
  <template>
    <button><content></content></button>
  </template>
  <script>
    MegaButton.prototype = {
      megaClick: function(e) {
        play('moo.mp3');
      }
    };
  </script>
</element>

http://html5-demos.appspot.com/stati.../index.html#63
http://html5-demos.appspot.com/stati.../index.html#66