Base64 Ein kleines JavaScript zur Demonstration von Base64 Encoding und Decoding. Decoded:><Encoded: HTML: base64.htm HTML (534 Bytes) 21.02.2021 00:28 <!DOCTYPE html > <html lang="en"> <head> <meta charset="utf-8" /> </head> <body> <form><label for="decoded">Decoded:</label><input type="text" id="decoded" /><button type="button" id="encode" title="encode value">></button><button type="button" id="decode" title="decode value"><</button><label for="encoded">Encoded:</label><input type="text" id="encoded" /></form> <script src="base64.js"></script> </body> </html> JavaScript: base64.js JavaScript (4,02 kByte) 20.12.2020 13:55 // coding: utf-8 /** Created by: Udo Schmal | https://www.gocher.me/ */ (function () { 'use strict'; 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 + Base64._keyStr.charAt(enc1) + Base64._keyStr.charAt(enc2) + Base64._keyStr.charAt(enc3) + Base64._keyStr.charAt(enc4); }; return output; }, // public method for decoding 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 = Base64._keyStr.indexOf(input.charAt(i++)); enc2 = Base64._keyStr.indexOf(input.charAt(i++)); enc3 = Base64._keyStr.indexOf(input.charAt(i++)); enc4 = Base64._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); } }; output = Base64._utf8_decode(output); 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 = 0, c1 = 0, c2 = 0; while ( i < utftext.length ) { c = utftext.charCodeAt(i); if (c < 128) { string += String.fromCharCode(c); i++; } else if((c > 191) && (c < 224)) { c1 = utftext.charCodeAt(i+1); string += String.fromCharCode(((c & 31) << 6) | (c1 & 63)); i += 2; } else { c1 = utftext.charCodeAt(i+1); c2 = utftext.charCodeAt(i+2); string += String.fromCharCode(((c & 15) << 12) | ((c1 & 63) << 6) | (c2 & 63)); i += 3; } }; return string; } } var encode = document.getElementById('encode'); if (encode) { encode.addEventListener('click', function (event) { var val_in = document.getElementById('decoded').value; var val_out = Base64.encode(val_in); document.getElementById('encoded').value = val_out; }); } var decode = document.getElementById('decode'); if (decode) { decode.addEventListener('click', function (event) { var val_in = document.getElementById('encoded').value; var val_out = Base64.decode(val_in); document.getElementById('decoded').value = val_out; }); } })(); Author: Udo Schmal, published: 10.10.2015, last modified: 06.09.2023