var Rounder = new Class.create({

   round: function(el)
   {
      var top    = "<div class='tl'><div class='tr'><div class='bl'><div id='" + el.id + "-inner' class='br content'>";
      var bottom = "</div></div></div></div>";

      el.innerHTML = top +  el.innerHTML + bottom;
   },

   roundTops: function(el)
   {
      var top    = "<div class='tl'><div class='tr content'>";
      var bottom = "</div></div>";

      el.innerHTML = top +  el.innerHTML + bottom;
   }
});

var rounder = new Rounder();

rounder.round($('page'));
rounder.round($('content'));