http://www.freecodecamp.com/bskydive 's solution for Bonfire: Mutations

bonfire-mutations#.js

// Bonfire: Mutations
// Author: @bskydive
// Challenge: http://www.freecodecamp.com/challenges/bonfire-mutations#
// Learn to Code at Free Code Camp (www.freecodecamp.com)

function mutation(arr) {
  var result=true;
  var i=0;
  var arr1ToLower = arr[0].toLowerCase();
  var arr2ToLower = arr[1].toLowerCase().split('');
  
  while (i<arr2ToLower.length){
    
    if (arr1ToLower.indexOf(arr2ToLower[i])<0) {result=false;i=arr2ToLower.length;}
    i++;
  }
  return result;
}

mutation(["hello", "hey"]);