Fix Function.bind polyfill.

Author: Eric Wendelin

polyfills.js

@@ -1,28 +1,22 @@
 // ES5 Polyfills
 // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind
 if (!Function.prototype.bind) {
-    Function.prototype.bind = function (oThis) {
-        if (typeof this !== 'function') {
-            throw new TypeError('Function.prototype.bind - what is trying to be bound is not callable');
-        }
-
-        var aArgs = Array.prototype.slice.call(arguments, 1);
-        var fToBind = this;
-        var NoOp = function () {
-        };
-        var fBound = function () {
-            return fToBind.apply(this instanceof NoOp && oThis ? this : oThis,
-                aArgs.concat(Array.prototype.slice.call(arguments)));
+    Function.prototype.bind = function bind(obj) {
+        var args = slice.call(arguments, 1);
+        var self = this;
+        var F = function() {};
+        var bounded = function() {
+            return self.apply(
+                this instanceof F ? this : (obj || {}),
+                args.concat(slice.call(arguments))
+            );
         };
-
-        NoOp.prototype = this.prototype;
-        fBound.prototype = new NoOp();
-
-        return fBound;
+        F.prototype = this.prototype || {};
+        bounded.prototype = new F();
+        return bounded;
     };
 }
 
-
 // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map
 if (!Array.prototype.map) {
     Array.prototype.map = function(callback, thisArg) {