[].map(function(value, index, array) {
    // ...
});

if (typeof Array.prototype.map != "function") {
  Array.prototype.map 
 
= function (fn, context) {
    var arr = [];
    if (typeof fn === "function") {
      for (var k = 0, length = this.length; k < length; k++) {      
         arr.push(fn.call(context, this[k], k, this));
      }
    }
    return arr;
  };
}