Fisher-Yates shuffle

ArrayShuffle.js

Array.prototype.shuffle = function() {
  var i = this.length, k, e;
  while (--i) {
    k = Math.floor(Math.random() * i);
    if (k != i) {
      e = this[i];
      this[i] = this[k];
      this[k] = e;
    }
  }
}