Base64 Javascript encode/decode library.

From http://www.webtoolkit.info/

include/base64a.js

+/**
+*
+*  Base64 encode / decode with array versions
+*
+*  Based on Base64 from:
+*  http://www.webtoolkit.info/
+*
+**/
+ 
+var Base64 = {
+ 
+    // private property
+    _keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
+ 
+    // public method for encoding
+    encode : function (input) {
+        var output = "";
+        var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
+        var i = 0;
+ 
+        input = Base64._utf8_encode(input);
+ 
+        while (i < input.length) {
+ 
+            chr1 = input.charCodeAt(i++);
+            chr2 = input.charCodeAt(i++);
+            chr3 = input.charCodeAt(i++);
+ 
+            enc1 = chr1 >> 2;
+            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
+            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
+            enc4 = chr3 & 63;
+ 
+            if (isNaN(chr2)) {
+                enc3 = enc4 = 64;
+            } else if (isNaN(chr3)) {
+                enc4 = 64;
+            }
+ 
+            output = output +
+            this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
+            this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
+ 
+        }
+ 
+        return output;
+    },
+ 
+    // public method for decoding to a string
+    decode : function (input) {
+        var output = "";
+        var chr1, chr2, chr3;
+        var enc1, enc2, enc3, enc4;
+        var i = 0;
+ 
+        input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
+ 
+        while (i < input.length) {
+ 
+            enc1 = this._keyStr.indexOf(input.charAt(i++));
+            enc2 = this._keyStr.indexOf(input.charAt(i++));
+            enc3 = this._keyStr.indexOf(input.charAt(i++));
+            enc4 = this._keyStr.indexOf(input.charAt(i++));
+ 
+            chr1 = (enc1 << 2) | (enc2 >> 4);
+            chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
+            chr3 = ((enc3 & 3) << 6) | enc4;
+ 
+            output = output + String.fromCharCode(chr1);
+ 
+            if (enc3 != 64) {
+                output = output + String.fromCharCode(chr2);
+            }
+            if (enc4 != 64) {
+                output = output + String.fromCharCode(chr3);
+            }
+ 
+        }
+    },
+
+    // public method for encoding an array
+    encode_array : function (input) {
+        var output = "";
+        var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
+        var i = 0;
+ 
+        while (i < input.length) {
+ 
+            chr1 = input[i++];
+            chr2 = input[i++];
+            chr3 = input[i++];
+
+            enc1 = chr1 >> 2;
+            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
+            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
+            enc4 = chr3 & 63;
+ 
+            if (isNaN(chr2)) {
+                enc3 = enc4 = 64;
+            } else if (isNaN(chr3)) {
+                enc4 = 64;
+            }
+ 
+            output = output +
+            this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
+            this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
+ 
+        }
+ 
+        return output;
+    },
+ 
+    // public method for decoding to an array
+    decode_array : function (input) {
+        var output = [];
+        var chr1, chr2, chr3;
+        var enc1, enc2, enc3, enc4;
+        var i = 0;
+ 
+        input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
+ 
+        while (i < input.length) {
+ 
+            enc1 = this._keyStr.indexOf(input.charAt(i++));
+            enc2 = this._keyStr.indexOf(input.charAt(i++));
+            enc3 = this._keyStr.indexOf(input.charAt(i++));
+            enc4 = this._keyStr.indexOf(input.charAt(i++));
+ 
+            chr1 = (enc1 << 2) | (enc2 >> 4);
+            chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
+            chr3 = ((enc3 & 3) << 6) | enc4;
+ 
+            output.push(chr1);
+ 
+            if (enc3 != 64) {
+                output.push(chr2);
+            }
+            if (enc4 != 64) {
+                output.push(chr3);
+            }
+ 
+        }
+ 
+        return output;
+ 
+    },
+ 
+    // private method for UTF-8 encoding
+    _utf8_encode : function (string) {
+        string = string.replace(/\r\n/g,"\n");
+        var utftext = "";
+ 
+        for (var n = 0; n < string.length; n++) {
+ 
+            var c = string.charCodeAt(n);
+ 
+            if (c < 128) {
+                utftext += String.fromCharCode(c);
+            }
+            else if((c > 127) && (c < 2048)) {
+                utftext += String.fromCharCode((c >> 6) | 192);
+                utftext += String.fromCharCode((c & 63) | 128);
+            }
+            else {
+                utftext += String.fromCharCode((c >> 12) | 224);
+                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
+                utftext += String.fromCharCode((c & 63) | 128);
+            }
+ 
+        }
+ 
+        return utftext;
+    },
+ 
+    // private method for UTF-8 decoding
+    _utf8_decode : function (utftext) {
+        var string = "";
+        var i = 0;
+        var c = c1 = c2 = 0;
+ 
+        while ( i < utftext.length ) {
+ 
+            c = utftext.charCodeAt(i);
+ 
+            if (c < 128) {
+                string += String.fromCharCode(c);
+                i++;
+            }
+            else if((c > 191) && (c < 224)) {
+                c2 = utftext.charCodeAt(i+1);
+                string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
+                i += 2;
+            }
+            else {
+                c2 = utftext.charCodeAt(i+1);
+                c3 = utftext.charCodeAt(i+2);
+                string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
+                i += 3;
+            }
+ 
+        }
+ 
+        return string;
+    }
+ 
+}