将以下代码复制另存为以.html后缀结尾的文件 访问即可测试
<!doctype html public "-//w3c//dtd html 4.01 transitional//en" "http://www.w3.org/tr/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=gb2312"> <title>base64编码加密</title> <script language="javascript"> var base64encodechars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; var base64decodechars = new Array( -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1); function base64encode(str) { var out, i, len; var c1, c2, c3; len = str.length; i = 0; out = ""; while (i < len) { c1 = str.charCodeAt(i++) & 0xff; if (i == len) { out += base64encodechars.charAt(c1 >> 2); out += base64encodechars.charAt((c1 & 0x3) << 4); out += "=="; break; } c2 = str.charCodeAt(i++); if (i == len) { out += base64encodechars.charAt(c1 >> 2); out += base64encodechars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xf0) >> 4)); out += base64encodechars.charAt((c2 & 0xf) << 2); out += "="; break; } c3 = str.charCodeAt(i++); out += base64encodechars.charAt(c1 >> 2); out += base64encodechars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xf0) >> 4)); out += base64encodechars.charAt(((c2 & 0xf) << 2) | ((c3 & 0xc0) >> 6)); out += base64encodechars.charAt(c3 & 0x3f); } return out; } function base64decode(str) { var c1, c2, c3, c4; var i, len, out; len = str.length; i = 0; out = ""; while (i < len) { do { c1 = base64decodechars[str.charCodeAt(i++) & 0xff]; } while (i < len && c1 == -1); if (c1 == -1) break; do { c2 = base64decodechars[str.charCodeAt(i++) & 0xff]; } while (i < len && c2 == -1); if (c2 == -1) break; out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)); do { c3 = str.charCodeAt(i++) & 0xff; if (c3 == 61) return out; c3 = base64decodechars[c3]; } while (i < len && c3 == -1); if (c3 == -1) break; out += String.fromCharCode(((c2 & 0xf) << 4) | ((c3 & 0x3c) >> 2)); do { c4 = str.charCodeAt(i++) & 0xff; if (c4 == 61) return out; c4 = base64decodechars[c4]; } while (i < len && c4 == -1); if (c4 == -1) break; out += String.fromCharCode(((c3 & 0x03) << 6) | c4); } return out; } function utf16to8(str) { var out, i, len, c; out = ""; len = str.length; for (i = 0; i < len; i++) { c = str.charCodeAt(i); if ((c >= 0x0001) && (c <= 0x007f)) { out += str.charAt(i); } else if (c > 0x07ff) { out += String.fromCharCode(0xe0 | ((c >> 12) & 0x0f)); out += String.fromCharCode(0x80 | ((c >> 6) & 0x3f)); out += String.fromCharCode(0x80 | ((c >> 0) & 0x3f)); } else { out += String.fromCharCode(0xc0 | ((c >> 6) & 0x1f)); out += String.fromCharCode(0x80 | ((c >> 0) & 0x3f)); } } return out; } function utf8to16(str) { var out, i, len, c; var char2, char3; out = ""; len = str.length; i = 0; while (i < len) { c = str.charCodeAt(i++); switch (c >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: // 0xxxxxxx out += str.charAt(i - 1); break; case 12: case 13: // 110x xxxx 10xx xxxx char2 = str.charCodeAt(i++); out += String.fromCharCode(((c & 0x1f) << 6) | (char2 & 0x3f)); break; case 14: // 1110 xxxx 10xx xxxx 10xx xxxx char2 = str.charCodeAt(i++); char3 = str.charCodeAt(i++); out += String.fromCharCode(((c & 0x0f) << 12) | ((char2 & 0x3f) << 6) | ((char3 & 0x3f) << 0)); break; } } return out; } function doit() { var f = document.f f.source.value = base64encode(utf16to8(f.source.value)); } function doit2() { var f = document.f f.source.value = utf8to16(base64decode(f.source.value)); } </script> </head> <body style="padding-left:50px;"> <h1 align="center">base64编码加密解密</h1> <form name="f"> 加密或解密的代码 <br> <textarea name="source" rows=22 cols=60 wrap="soft"></textarea><br> <input type=button value="加密" onclick="doit()"><input type=button value="解密" onclick="doit2()"> </form> </body> </html>
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