How to convert an arraybuffer to string in javascript

arrayBufferToString : function (arrayBuffer) {
var binary_string = '';
bytes = new Uint8Array(arrayBuffer);
for (var i = 0; i < bytes.byteLength; i++) {
    binary_string += String.fromCharCode(bytes[i]);
}
return binary_string;
},

XMLHttpRequest send binary data

XMLHttpRequest.prototype.binarySend = function(string) {
   var bytes = Array.prototype.map.call(string, function(c) {
     return c.charCodeAt(0) & 0xff;
   });
   this.send(new Uint8Array(bytes).buffer);