var StripyTables =
{
  init: function()
  {
    var tables = document.getElementsByTagName("table");
    for (var i = 0, ii = tables.length; i < ii; i++)
    {
      var tbodys = tables[i].getElementsByTagName("tbody");
      for (var j = 0, jj = tbodys.length; j < jj; j++)
      {
        var rows = tbodys[j].getElementsByTagName("tr");
        for (var k = 1, kk = rows.length; k < kk; k += 2)
        {
          rows[k].className = "alt";
        }
      }
    }    
  }
};

StripyTables.init();