permutations.js

// Many thanks to http://stackoverflow.com/questions/9960908/permutations-in-javascript/9960925#9960925
permutations = function(arr){
  var permArr = [],
      usedChars = [];

  function permute(input) {
    var i, ch;
    for (i = 0; i < input.length; i++) {
      ch = input.splice(i, 1)[0];
      usedChars.push(ch);
      if (input.length == 0) {
        permArr.push(usedChars.slice());
      }
      permute(input);
      input.splice(i, 0, ch);
      usedChars.pop();
    }
    return permArr;
  };
  return permute(arr);
};