https://xoltron.github.io/xoltcookie/base64.js

1/**
2*
3*  Base64 encode / decode
4*  http://www.webtoolkit.info/
5*
6**/
7 
8var Base64 = {
9 
10	// private property
11	_keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
12 
13	// public method for encoding
14	encode : function (input) {
15		var output = "";
16		var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
17		var i = 0;
18 
19		input = Base64._utf8_encode(input);
20 
21		while (i < input.length) {
22 
23			chr1 = input.charCodeAt(i++);
24			chr2 = input.charCodeAt(i++);
25			chr3 = input.charCodeAt(i++);
26 
27			enc1 = chr1 >> 2;
28			enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
29			enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
30			enc4 = chr3 & 63;
31 
32			if (isNaN(chr2)) {
33				enc3 = enc4 = 64;
34			} else if (isNaN(chr3)) {
35				enc4 = 64;
36			}
37 
38			output = output +
39			this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
40			this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
41 
42		}
43 
44		return output;
45	},
46 
47	// public method for decoding
48	decode : function (input) {
49		var output = "";
50		var chr1, chr2, chr3;
51		var enc1, enc2, enc3, enc4;
52		var i = 0;
53 
54		input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
55 
56		while (i < input.length) {
57 
58			enc1 = this._keyStr.indexOf(input.charAt(i++));
59			enc2 = this._keyStr.indexOf(input.charAt(i++));
60			enc3 = this._keyStr.indexOf(input.charAt(i++));
61			enc4 = this._keyStr.indexOf(input.charAt(i++));
62 
63			chr1 = (enc1 << 2) | (enc2 >> 4);
64			chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
65			chr3 = ((enc3 & 3) << 6) | enc4;
66 
67			output = output + String.fromCharCode(chr1);
68 
69			if (enc3 != 64) {
70				output = output + String.fromCharCode(chr2);
71			}
72			if (enc4 != 64) {
73				output = output + String.fromCharCode(chr3);
74			}
75 
76		}
77 
78		output = Base64._utf8_decode(output);
79 
80		return output;
81 
82	},
83 
84	// private method for UTF-8 encoding
85	_utf8_encode : function (string) {
86		string = string.replace(/\r\n/g,"\n");
87		var utftext = "";
88 
89		for (var n = 0; n < string.length; n++) {
90 
91			var c = string.charCodeAt(n);
92 
93			if (c < 128) {
94				utftext += String.fromCharCode(c);
95			}
96			else if((c > 127) && (c < 2048)) {
97				utftext += String.fromCharCode((c >> 6) | 192);
98				utftext += String.fromCharCode((c & 63) | 128);
99			}
100			else {
101				utftext += String.fromCharCode((c >> 12) | 224);
102				utftext += String.fromCharCode(((c >> 6) & 63) | 128);
103				utftext += String.fromCharCode((c & 63) | 128);
104			}
105 
106		}
107 
108		return utftext;
109	},
110 
111	// private method for UTF-8 decoding
112	_utf8_decode : function (utftext) {
113		var string = "";
114		var i = 0;
115		var c = c1 = c2 = 0;
116 
117		while ( i < utftext.length ) {
118 
119			c = utftext.charCodeAt(i);
120 
121			if (c < 128) {
122				string += String.fromCharCode(c);
123				i++;
124			}
125			else if((c > 191) && (c < 224)) {
126				c2 = utftext.charCodeAt(i+1);
127				string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
128				i += 2;
129			}
130			else {
131				c2 = utftext.charCodeAt(i+1);
132				c3 = utftext.charCodeAt(i+2);
133				string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
134				i += 3;
135			}
136 
137		}
138 
139		return string;
140	}
141 
142}