JS: Padding

<script type="text/javascript" type="text/javascript">
  var STR_PAD_LEFT = 1;
  var STR_PAD_RIGHT = 2;
  var STR_PAD_BOTH = 3;

  function pad(str, len, pad, dir) {
    if (typeof (len) == "undefined") { var len = 0; }
    if (typeof (pad) == "undefined") { var pad = ' '; }
    if (typeof (dir) == "undefined") { var dir = STR_PAD_RIGHT; }

    if (len + 1 >= str.length) {
      switch (dir) {
        case STR_PAD_LEFT:
          str = Array(len + 1 - str.length).join(pad) + str;
          break;
          
        case STR_PAD_BOTH:
          var right = Math.ceil((padlen = len - str.length) / 2);
          var left = padlen - right;
          str = Array(left + 1).join(pad) + str + Array(right + 1).join(pad);
          break;

        default:
          str = str + Array(len + 1 - str.length).join(pad);
          break;
      } // switch
    }
    return str;
  }
  alert(pad('ravi', 20, ' d ', STR_PAD_RIGHT));
</script>