Non-bias random array shuffle. For more about the Fisher–Yates shuffle, see the Wikipedia article and Jeff Atwood’s post, “The Danger of Naïveté” (2007). Sauce: http://bost.ocks.org/mike/shuffle/

shuffle.js

function shuffle(array) {
  var m = array.length, t, i;

  // While there remain elements to shuffle…
  while (m) {

    // Pick a remaining element…
    i = Math.floor(Math.random() * m--);

    // And swap it with the current element.
    t = array[m];
    array[m] = array[i];
    array[i] = t;
  }

  return array;
}