function shuffle(array) {

  var currentIndex = array.length, temporaryValue, randomIndex;

​

  // While there remain elements to shuffle...

  while (0 !== currentIndex) {

​

    // Pick a remaining element...

    randomIndex = Math.floor(Math.random() * currentIndex);

    currentIndex -= 1;

​

    // And swap it with the current element.

    temporaryValue = array[currentIndex];

    array[currentIndex] = array[randomIndex];

    array[randomIndex] = temporaryValue;

  }

​

  return array;

}

​

var sorted = [];

var shuffled = [];

for (var i = 0; i < 1000; i++) {

  sorted.push('a' + i);

  shuffled.push('a' + i);

}

​

shuffled = shuffle(shuffled);

​

​