Fix regression: Old browser support

lib/b64.js

@@ -1,9 +1,12 @@
 var lookup = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
 
-
 ;(function (exports) {
 	'use strict';
 
+  var Arr = (typeof Uint8Array !== 'undefined')
+    ? Uint8Array
+    : Array
+
 	var ZERO   = '0'.charCodeAt(0)
 	var PLUS   = '+'.charCodeAt(0)
 	var SLASH  = '/'.charCodeAt(0)
@@ -40,10 +43,10 @@ var lookup = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
 		// if there is only one, then the three characters before it represent 2 bytes
 		// this is just a cheap hack to not do indexOf twice
 		var len = b64.length
-		placeHolders = '=' === b64[len - 2] ? 2 : '=' === b64[len - 1] ? 1 : 0
+		placeHolders = '=' === b64.charAt(len - 2) ? 2 : '=' === b64.charAt(len - 1) ? 1 : 0
 
 		// base64 is 4/3 + up to two characters of the original data
-		arr = new Uint8Array(b64.length * 3 / 4 - placeHolders);
+		arr = new Arr(b64.length * 3 / 4 - placeHolders);
 
 		// if there are placeholders, only get up to the last complete 4 chars
 
@@ -118,6 +121,5 @@ var lookup = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
 
 	module.exports.toByteArray = b64ToByteArray;
 	module.exports.fromByteArray = uint8ToBase64;
-	module.exports.lookup = lookup
 }());