Base64

var Base64 = function() {
            var _key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
            var _keyRe = new RegExp("[^" + _key + "=]", "g");
            return {
                encode: function(input) {
                    var output = "";
                    var len = input.length, i = 0, padding = 3 - (len % 3);
                    while (i < len) {
                        var byte1 = input.charCodeAt(i++);
                        var byte2 = input.charCodeAt(i++) || 0;
                        var byte3 = input.charCodeAt(i++) || 0;
                        var index1 = byte1 >> 2;
                        var index2 = (byte1 & 3) << 4 | byte2 >> 4;
                        var index3 = (byte2 & 15) << 2 | byte3 >> 6;
                        var index4 = byte3 & 63;
                        output += _key.charAt(index1) + _key.charAt(index2) + _key.charAt(index3) + _key.charAt(index4);
                    }
                    if (padding)
                        output = output.slice(0, output.length - padding) + (padding == 1 ? "=" : "==");
                    return output;
                },
                decode: function(input) {
                    input = input.replace(_keyRe, "");
                    var output = "";
                    var i = 0, len = input.length, padding = len - input.indexOf("=");
                    while (i < len) {
                        var byte1 = _key.indexOf(input.substr(i++, 1));
                        var byte2 = _key.indexOf(input.substr(i++, 1));
                        var byte3 = _key.indexOf(input.substr(i++, 1));
                        var byte4 = _key.indexOf(input.substr(i++, 1));
                        var char1 = byte1 << 2 | byte2 >> 4;
                        var char2 = ((byte2 & 15) << 4) | (byte3 >> 2);
                        var char3 = ((byte3 & 3) << 6) | byte4 & 63;
                        output += String.fromCharCode(char1) + String.fromCharCode(char2) + String.fromCharCode(char3);
                    }
                    if (padding)
                        output = output.substr(0, output.length - padding);
                    return output;
                }
            };
        } ();