Created
December 5, 2012 16:06
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base64 encode/decode
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| https://developer.mozilla.org/en-US/docs/DOM/window.btoa | |
| https://developer.mozilla.org/en-US/docs/DOM/window.atob | |
| <html> | |
| <head> | |
| <title>base64 Encoding/Decoding</title> | |
| </head> | |
| <script type="text/javascript"> | |
| <!-- | |
| var keyStr = "ABCDEFGHIJKLMNOP" + | |
| "QRSTUVWXYZabcdef" + | |
| "ghijklmnopqrstuv" + | |
| "wxyz0123456789+/" + | |
| "="; | |
| function encode64(input) { | |
| input = escape(input); | |
| var output = ""; | |
| var chr1, chr2, chr3 = ""; | |
| var enc1, enc2, enc3, enc4 = ""; | |
| var i = 0; | |
| do { | |
| 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 + | |
| keyStr.charAt(enc1) + | |
| keyStr.charAt(enc2) + | |
| keyStr.charAt(enc3) + | |
| keyStr.charAt(enc4); | |
| chr1 = chr2 = chr3 = ""; | |
| enc1 = enc2 = enc3 = enc4 = ""; | |
| } while (i < input.length); | |
| return output; | |
| } | |
| function decode64(input) { | |
| var output = ""; | |
| var chr1, chr2, chr3 = ""; | |
| var enc1, enc2, enc3, enc4 = ""; | |
| var i = 0; | |
| // remove all characters that are not A-Z, a-z, 0-9, +, /, or = | |
| var base64test = /[^A-Za-z0-9\+\/\=]/g; | |
| if (base64test.exec(input)) { | |
| alert("There were invalid base64 characters in the input text.\n" + | |
| "Valid base64 characters are A-Z, a-z, 0-9, '+', '/',and '='\n" + | |
| "Expect errors in decoding."); | |
| } | |
| input = input.replace(/[^A-Za-z0-9\+\/\=]/g, ""); | |
| do { | |
| enc1 = keyStr.indexOf(input.charAt(i++)); | |
| enc2 = keyStr.indexOf(input.charAt(i++)); | |
| enc3 = keyStr.indexOf(input.charAt(i++)); | |
| enc4 = 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); | |
| } | |
| chr1 = chr2 = chr3 = ""; | |
| enc1 = enc2 = enc3 = enc4 = ""; | |
| } while (i < input.length); | |
| return unescape(output); | |
| } | |
| //--></script> | |
| <body> | |
| <form name="base64Form"> | |
| Type in the message you want to encode in base64, or paste<br> | |
| base64 encoded text into the text field, select Encode or Decode, <br> | |
| and click the button!<br> | |
| <textarea name="theText" cols="40" rows="6"></textarea><br> | |
| <input type="button" name="encode" value="Encode to base64" | |
| onClick="document.base64Form.theText.value=encode64(document.base64Form.theText.value);"> | |
| <input type="button" name="decode" value="Decode from base64" | |
| onClick="document.base64Form.theText.value=decode64(document.base64Form.theText.value);"> | |
| </form> | |
| </body> | |
| </html> |
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