Base64编码解码

收藏的Base64编码/解码。

在一个外国网站看到的，不过对中文不支持。

自己加入了escape,unescape，对中文也支持了。

先用escape()对中文进行编码，然后再进行base64编码。

解码时，再加入unescape()对中文进行解码。

<html>

<head>

<title>base64 Encoding/Decoding</title>

</head>

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>

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>

<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>

引用自：
http://www2.cnblogs.com/vibration/articles/7392.html

posted on 2005-04-19 13:30 小迪阅读(912) 评论(0) 收藏举报