function hasClass(obj) {
     var result = false;
     if (obj.getAttributeNode("class") != null) {
         result = obj.getAttributeNode("class").value;
     }
     return result;
  }   

 function stripe(id) {
    var even = false;
  
    var evenColor = arguments[1] ? arguments[1] : "#fff";
    var oddColor = arguments[2] ? arguments[2] : "#eee";

    var table = document.getElementById(id);
    if (! table) { return; }
    
    var tbodies = table.getElementsByTagName("tbody");

    for (var h = 0; h < tbodies.length; h++) {
    
      var trs = tbodies[h].getElementsByTagName("tr");
      for (var i = 0; i < trs.length; i++) {
        if (! hasClass(trs[i]) &&
            ! trs[i].style.backgroundColor) {
          var tds = trs[i].getElementsByTagName("td");
          for (var j = 0; j < tds.length; j++) {
        
            var mytd = tds[j];

            mytd.style.backgroundColor =
                even ? evenColor : oddColor;            
          }
        }
        even =  ! even;
      }
    }
  }