function array_pad (input, pad_size, pad_value) {
  // http://kevin.vanzonneveld.net
  // +   original by: Waldo Malqui Silva
  // *     example 1: array_pad([ 7, 8, 9 ], 2, 'a');
  // *     returns 1: [ 7, 8, 9]
  // *     example 2: array_pad([ 7, 8, 9 ], 5, 'a');
  // *     returns 2: [ 7, 8, 9, 'a', 'a']
  // *     example 3: array_pad([ 7, 8, 9 ], 5, 2);
  // *     returns 3: [ 7, 8, 9, 2, 2]
  // *     example 4: array_pad([ 7, 8, 9 ], -5, 'a');
  // *     returns 4: [ 'a', 'a', 7, 8, 9 ]
  var pad = [],
    newArray = [],
    newLength,
    diff = 0,
    i = 0;

  if (Object.prototype.toString.call(input) === '[object Array]' && !isNaN(pad_size)) {
    newLength = ((pad_size < 0) ? (pad_size * -1) : pad_size);
    diff = newLength - input.length;

    if (diff > 0) {
      for (i = 0; i < diff; i++) {
        newArray[i] = pad_value;
      }
      pad = ((pad_size < 0) ? newArray.concat(input) : input.concat(newArray));
    } else {
      pad = input;
    }
  }

  return pad;
}

array_pad([ 7, 8, 9 ], 2, 'a');

[ 7, 8, 9]

array_pad([ 7, 8, 9 ], 5, 'a');

[ 7, 8, 9, 'a', 'a']

array_pad([ 7, 8, 9 ], 5, 2);

[ 7, 8, 9, 2, 2]