JS实现的3des+base64加密解密算法完整示例

更新时间：2020-07-09 21:30:01 作者：startmvc

本文实例讲述了JS实现的3des+base64加密解密算法。分享给大家供大家参考，具体如下：1.index.

本文实例讲述了JS实现的3des+base64加密解密算法。分享给大家供大家参考，具体如下：

1. index.html：


<html xmlns="http://www.w3.org/1999/xhtml">
<head>
 <title>www.jb51.net BASE64编码</title>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 <script type="text/javascript" src="Base64.js"></script>
 <script type="text/javascript" src="DES3.js"></script>
</head>
<body>
<script type="text/javascript">
var str = "网址：//www.jb51.net";
document.write("原始字符串:</br>"+str);
var base64 = BASE64.encoder(str);//返回编码后的字符
document.write("</br>BASE64后:</br>"+base64);
//alert(base64);
var unicode= BASE64.decoder(base64);//返回会解码后的字符串。
//alert(unicode);
document.write("</br>还原:</br>"+unicode);
//var str= "你好123hello";
var key = "qXSdHWfbSZaaLeHBRhLgxBiG";
//alert(decrypt_3des);
var des3en = DES3.encrypt(key,str);
document.write("</br>des3加密:</br>"+des3en);
document.write("</br>des3解密:</br>"+DES3.decrypt(key,des3en));
</script>
</body>

2. DES3.js文件：


/** 
 * DES 加密算法 
 * 
 * 该函数接受一个 8 字节字符串作为普通 DES 算法的密钥（也就是 64 位，但是算法只使用 56 位），或者接受一个 24 字节字符串作为 3DES 
 * 算法的密钥；第二个参数是要加密或解密的信息字符串；第三个布尔值参数用来说明信息是加密还是解密；接下来的可选参数 mode 如果是 0 表示 ECB 
 * 模式，1 表示 CBC 模式，默认是 ECB 模式；最后一个可选项是一个 8 字节的输入向量字符串（在 ECB 模式下不使用）。返回的密文是字符串。 
 * 
 * 参数： <br> 
 * key: 8字节字符串作为普通 DES 算法的密钥,或 24 字节字符串作为 3DES <br> 
 * message： 加密或解密的信息字符串<br> 
 * encrypt: 布尔值参数用来说明信息是加密还是解密<br> 
 * mode: 1:CBC模式，0:ECB模式(默认)<br> 
 * iv:<br> 
 * padding: 可选项, 8字节的输入向量字符串（在 ECB 模式下不使用） 
 */
//this takes the key, the message, and whether to encrypt or decrypt
function des (key, message, encrypt, mode, iv, padding) {
 if(encrypt) //如果是加密的话，首先转换编码
 message = unescape(encodeURIComponent(message));
 //declaring this locally speeds things up a bit
 var spfunction1 = new Array (0x1010400,0,0x10000,0x1010404,0x1010004,0x10404,0x4,0x10000,0x400,0x1010400,0x1010404,0x400,0x1000404,0x1010004,0x1000000,0x4,0x404,0x1000400,0x1000400,0x10400,0x10400,0x1010000,0x1010000,0x1000404,0x10004,0x1000004,0x1000004,0x10004,0,0x404,0x10404,0x1000000,0x10000,0x1010404,0x4,0x1010000,0x1010400,0x1000000,0x1000000,0x400,0x1010004,0x10000,0x10400,0x1000004,0x400,0x4,0x1000404,0x10404,0x1010404,0x10004,0x1010000,0x1000404,0x1000004,0x404,0x10404,0x1010400,0x404,0x1000400,0x1000400,0,0x10004,0x10400,0,0x1010004);
 var spfunction2 = new Array (-0x7fef7fe0,-0x7fff8000,0x8000,0x108020,0x100000,0x20,-0x7fefffe0,-0x7fff7fe0,-0x7fffffe0,-0x7fef7fe0,-0x7fef8000,-0x80000000,-0x7fff8000,0x100000,0x20,-0x7fefffe0,0x108000,0x100020,-0x7fff7fe0,0,-0x80000000,0x8000,0x108020,-0x7ff00000,0x100020,-0x7fffffe0,0,0x108000,0x8020,-0x7fef8000,-0x7ff00000,0x8020,0,0x108020,-0x7fefffe0,0x100000,-0x7fff7fe0,-0x7ff00000,-0x7fef8000,0x8000,-0x7ff00000,-0x7fff8000,0x20,-0x7fef7fe0,0x108020,0x20,0x8000,-0x80000000,0x8020,-0x7fef8000,0x100000,-0x7fffffe0,0x100020,-0x7fff7fe0,-0x7fffffe0,0x100020,0x108000,0,-0x7fff8000,0x8020,-0x80000000,-0x7fefffe0,-0x7fef7fe0,0x108000);
 var spfunction3 = new Array (0x208,0x8020200,0,0x8020008,0x8000200,0,0x20208,0x8000200,0x20008,0x8000008,0x8000008,0x20000,0x8020208,0x20008,0x8020000,0x208,0x8000000,0x8,0x8020200,0x200,0x20200,0x8020000,0x8020008,0x20208,0x8000208,0x20200,0x20000,0x8000208,0x8,0x8020208,0x200,0x8000000,0x8020200,0x8000000,0x20008,0x208,0x20000,0x8020200,0x8000200,0,0x200,0x20008,0x8020208,0x8000200,0x8000008,0x200,0,0x8020008,0x8000208,0x20000,0x8000000,0x8020208,0x8,0x20208,0x20200,0x8000008,0x8020000,0x8000208,0x208,0x8020000,0x20208,0x8,0x8020008,0x20200);
 var spfunction4 = new Array (0x802001,0x2081,0x2081,0x80,0x802080,0x800081,0x800001,0x2001,0,0x802000,0x802000,0x802081,0x81,0,0x800080,0x800001,0x1,0x2000,0x800000,0x802001,0x80,0x800000,0x2001,0x2080,0x800081,0x1,0x2080,0x800080,0x2000,0x802080,0x802081,0x81,0x800080,0x800001,0x802000,0x802081,0x81,0,0,0x802000,0x2080,0x800080,0x800081,0x1,0x802001,0x2081,0x2081,0x80,0x802081,0x81,0x1,0x2000,0x800001,0x2001,0x802080,0x800081,0x2001,0x2080,0x800000,0x802001,0x80,0x800000,0x2000,0x802080);
 var spfunction5 = new Array (0x100,0x2080100,0x2080000,0x42000100,0x80000,0x100,0x40000000,0x2080000,0x40080100,0x80000,0x2000100,0x40080100,0x42000100,0x42080000,0x80100,0x40000000,0x2000000,0x40080000,0x40080000,0,0x40000100,0x42080100,0x42080100,0x2000100,0x42080000,0x40000100,0,0x42000000,0x2080100,0x2000000,0x42000000,0x80100,0x80000,0x42000100,0x100,0x2000000,0x40000000,0x2080000,0x42000100,0x40080100,0x2000100,0x40000000,0x42080000,0x2080100,0x40080100,0x100,0x2000000,0x42080000,0x42080100,0x80100,0x42000000,0x42080100,0x2080000,0,0x40080000,0x42000000,0x80100,0x2000100,0x40000100,0x80000,0,0x40080000,0x2080100,0x40000100);
 var spfunction6 = new Array (0x20000010,0x20400000,0x4000,0x20404010,0x20400000,0x10,0x20404010,0x400000,0x20004000,0x404010,0x400000,0x20000010,0x400010,0x20004000,0x20000000,0x4010,0,0x400010,0x20004010,0x4000,0x404000,0x20004010,0x10,0x20400010,0x20400010,0,0x404010,0x20404000,0x4010,0x404000,0x20404000,0x20000000,0x20004000,0x10,0x20400010,0x404000,0x20404010,0x400000,0x4010,0x20000010,0x400000,0x20004000,0x20000000,0x4010,0x20000010,0x20404010,0x404000,0x20400000,0x404010,0x20404000,0,0x20400010,0x10,0x4000,0x20400000,0x404010,0x4000,0x400010,0x20004010,0,0x20404000,0x20000000,0x400010,0x20004010);
 var spfunction7 = new Array (0x200000,0x4200002,0x4000802,0,0x800,0x4000802,0x200802,0x4200800,0x4200802,0x200000,0,0x4000002,0x2,0x4000000,0x4200002,0x802,0x4000800,0x200802,0x200002,0x4000800,0x4000002,0x4200000,0x4200800,0x200002,0x4200000,0x800,0x802,0x4200802,0x200800,0x2,0x4000000,0x200800,0x4000000,0x200800,0x200000,0x4000802,0x4000802,0x4200002,0x4200002,0x2,0x200002,0x4000000,0x4000800,0x200000,0x4200800,0x802,0x200802,0x4200800,0x802,0x4000002,0x4200802,0x4200000,0x200800,0,0x2,0x4200802,0,0x200802,0x4200000,0x800,0x4000002,0x4000800,0x800,0x200002);
 var spfunction8 = new Array (0x10001040,0x1000,0x40000,0x10041040,0x10000000,0x10001040,0x40,0x10000000,0x40040,0x10040000,0x10041040,0x41000,0x10041000,0x41040,0x1000,0x40,0x10040000,0x10000040,0x10001000,0x1040,0x41000,0x40040,0x10040040,0x10041000,0x1040,0,0,0x10040040,0x10000040,0x10001000,0x41040,0x40000,0x41040,0x40000,0x10041000,0x1000,0x40,0x10040040,0x1000,0x41040,0x10001000,0x40,0x10000040,0x10040000,0x10040040,0x10000000,0x40000,0x10001040,0,0x10041040,0x40040,0x10000040,0x10040000,0x10001000,0x10001040,0,0x10041040,0x41000,0x41000,0x1040,0x1040,0x40040,0x10000000,0x10041000);
 //create the 16 or 48 subkeys we will need
 var keys = des_createKeys (key);
 var m=0, i, j, temp, temp2, right1, right2, left, right, looping;
 var cbcleft, cbcleft2, cbcright, cbcright2
 var endloop, loopinc;
 var len = message.length;
 var chunk = 0;
 //set up the loops for single and triple des
 var iterations = keys.length == 32 ? 3 : 9; //single or triple des
 if (iterations == 3) {looping = encrypt ? new Array (0, 32, 2) : new Array (30, -2, -2);}
 else {looping = encrypt ? new Array (0, 32, 2, 62, 30, -2, 64, 96, 2) : new Array (94, 62, -2, 32, 64, 2, 30, -2, -2);}
 //pad the message depending on the padding parameter
 if (padding == 2) message += " "; //pad the message with spaces
 else if (padding == 1) {
 if(encrypt) {
 temp = 8-(len%8);
 message += String.fromCharCode(temp,temp,temp,temp,temp,temp,temp,temp);
 if (temp===8) len+=8;
 }
 } //PKCS7 padding
 else if (!padding) message += "\0\0\0\0\0\0\0\0"; //pad the message out with null bytes
 //store the result here
 var result = "";
 var tempresult = "";
 if (mode == 1) { //CBC mode
 cbcleft = (iv.charCodeAt(m++) << 24) | (iv.charCodeAt(m++) << 16) | (iv.charCodeAt(m++) << 8) | iv.charCodeAt(m++);
 cbcright = (iv.charCodeAt(m++) << 24) | (iv.charCodeAt(m++) << 16) | (iv.charCodeAt(m++) << 8) | iv.charCodeAt(m++);
 m=0;
 }
 //loop through each 64 bit chunk of the message
 while (m < len) {
 left = (message.charCodeAt(m++) << 24) | (message.charCodeAt(m++) << 16) | (message.charCodeAt(m++) << 8) | message.charCodeAt(m++);
 right = (message.charCodeAt(m++) << 24) | (message.charCodeAt(m++) << 16) | (message.charCodeAt(m++) << 8) | message.charCodeAt(m++);
 //for Cipher Block Chaining mode, xor the message with the previous result
 if (mode == 1) {if (encrypt) {left ^= cbcleft; right ^= cbcright;} else {cbcleft2 = cbcleft; cbcright2 = cbcright; cbcleft = left; cbcright = right;}}
 //first each 64 but chunk of the message must be permuted according to IP
 temp = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4);
 temp = ((left >>> 16) ^ right) & 0x0000ffff; right ^= temp; left ^= (temp << 16);
 temp = ((right >>> 2) ^ left) & 0x33333333; left ^= temp; right ^= (temp << 2);
 temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8);
 temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1);
 left = ((left << 1) | (left >>> 31));
 right = ((right << 1) | (right >>> 31));
 //do this either 1 or 3 times for each chunk of the message
 for (j=0; j<iterations; j+=3) {
 endloop = looping[j+1];
 loopinc = looping[j+2];
 //now go through and perform the encryption or decryption
 for (i=looping[j]; i!=endloop; i+=loopinc) { //for efficiency
 right1 = right ^ keys[i];
 right2 = ((right >>> 4) | (right << 28)) ^ keys[i+1];
 //the result is attained by passing these bytes through the S selection functions
 temp = left;
 left = right;
 right = temp ^ (spfunction2[(right1 >>> 24) & 0x3f] | spfunction4[(right1 >>> 16) & 0x3f]
 | spfunction6[(right1 >>> 8) & 0x3f] | spfunction8[right1 & 0x3f]
 | spfunction1[(right2 >>> 24) & 0x3f] | spfunction3[(right2 >>> 16) & 0x3f]
 | spfunction5[(right2 >>> 8) & 0x3f] | spfunction7[right2 & 0x3f]);
 }
 temp = left; left = right; right = temp; //unreverse left and right
 } //for either 1 or 3 iterations
 //move then each one bit to the right
 left = ((left >>> 1) | (left << 31));
 right = ((right >>> 1) | (right << 31));
 //now perform IP-1, which is IP in the opposite direction
 temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1);
 temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8);
 temp = ((right >>> 2) ^ left) & 0x33333333; left ^= temp; right ^= (temp << 2);
 temp = ((left >>> 16) ^ right) & 0x0000ffff; right ^= temp; left ^= (temp << 16);
 temp = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4);
 //for Cipher Block Chaining mode, xor the message with the previous result
 if (mode == 1) {if (encrypt) {cbcleft = left; cbcright = right;} else {left ^= cbcleft2; right ^= cbcright2;}}
 tempresult += String.fromCharCode ((left>>>24), ((left>>>16) & 0xff), ((left>>>8) & 0xff), (left & 0xff), (right>>>24), ((right>>>16) & 0xff), ((right>>>8) & 0xff), (right & 0xff));
 chunk += 8;
 if (chunk == 512) {result += tempresult; tempresult = ""; chunk = 0;}
 } //for every 8 characters, or 64 bits in the message
 //return the result as an array
 result += tempresult;
 result = result.replace(/\0*$/g, "");
 if(!encrypt ) { //如果是解密的话，解密结束后对PKCS7 padding进行解码，并转换成utf-8编码
 if(padding === 1) { //PKCS7 padding解码
 var len = result.length, paddingChars = 0;
 len && (paddingChars = result.charCodeAt(len-1));
 (paddingChars <= 8) && (result = result.substring(0, len - paddingChars));
 }
 //转换成UTF-8编码
 result = decodeURIComponent(escape(result));
 }
 return result;
} //end of des
//des_createKeys
//this takes as input a 64 bit key (even though only 56 bits are used)
//as an array of 2 integers, and returns 16 48 bit keys
function des_createKeys (key) {
 //declaring this locally speeds things up a bit
 var pc2bytes0 = new Array (0,0x4,0x20000000,0x20000004,0x10000,0x10004,0x20010000,0x20010004,0x200,0x204,0x20000200,0x20000204,0x10200,0x10204,0x20010200,0x20010204);
 var pc2bytes1 = new Array (0,0x1,0x100000,0x100001,0x4000000,0x4000001,0x4100000,0x4100001,0x100,0x101,0x100100,0x100101,0x4000100,0x4000101,0x4100100,0x4100101);
 var pc2bytes2 = new Array (0,0x8,0x800,0x808,0x1000000,0x1000008,0x1000800,0x1000808,0,0x8,0x800,0x808,0x1000000,0x1000008,0x1000800,0x1000808);
 var pc2bytes3 = new Array (0,0x200000,0x8000000,0x8200000,0x2000,0x202000,0x8002000,0x8202000,0x20000,0x220000,0x8020000,0x8220000,0x22000,0x222000,0x8022000,0x8222000);
 var pc2bytes4 = new Array (0,0x40000,0x10,0x40010,0,0x40000,0x10,0x40010,0x1000,0x41000,0x1010,0x41010,0x1000,0x41000,0x1010,0x41010);
 var pc2bytes5 = new Array (0,0x400,0x20,0x420,0,0x400,0x20,0x420,0x2000000,0x2000400,0x2000020,0x2000420,0x2000000,0x2000400,0x2000020,0x2000420);
 var pc2bytes6 = new Array (0,0x10000000,0x80000,0x10080000,0x2,0x10000002,0x80002,0x10080002,0,0x10000000,0x80000,0x10080000,0x2,0x10000002,0x80002,0x10080002);
 var pc2bytes7 = new Array (0,0x10000,0x800,0x10800,0x20000000,0x20010000,0x20000800,0x20010800,0x20000,0x30000,0x20800,0x30800,0x20020000,0x20030000,0x20020800,0x20030800);
 var pc2bytes8 = new Array (0,0x40000,0,0x40000,0x2,0x40002,0x2,0x40002,0x2000000,0x2040000,0x2000000,0x2040000,0x2000002,0x2040002,0x2000002,0x2040002);
 var pc2bytes9 = new Array (0,0x10000000,0x8,0x10000008,0,0x10000000,0x8,0x10000008,0x400,0x10000400,0x408,0x10000408,0x400,0x10000400,0x408,0x10000408);
 var pc2bytes10 = new Array (0,0x20,0,0x20,0x100000,0x100020,0x100000,0x100020,0x2000,0x2020,0x2000,0x2020,0x102000,0x102020,0x102000,0x102020);
 var pc2bytes11 = new Array (0,0x1000000,0x200,0x1000200,0x200000,0x1200000,0x200200,0x1200200,0x4000000,0x5000000,0x4000200,0x5000200,0x4200000,0x5200000,0x4200200,0x5200200);
 var pc2bytes12 = new Array (0,0x1000,0x8000000,0x8001000,0x80000,0x81000,0x8080000,0x8081000,0x10,0x1010,0x8000010,0x8001010,0x80010,0x81010,0x8080010,0x8081010);
 var pc2bytes13 = new Array (0,0x4,0x100,0x104,0,0x4,0x100,0x104,0x1,0x5,0x101,0x105,0x1,0x5,0x101,0x105);
 //how many iterations (1 for des, 3 for triple des)
 var iterations = key.length > 8 ? 3 : 1; //changed by Paul 16/6/2007 to use Triple DES for 9+ byte keys
 //stores the return keys
 var keys = new Array (32 * iterations);
 //now define the left shifts which need to be done
 var shifts = new Array (0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0);
 //other variables
 var lefttemp, righttemp, m=0, n=0, temp;
 for (var j=0; j<iterations; j++) { //either 1 or 3 iterations
 var left = (key.charCodeAt(m++) << 24) | (key.charCodeAt(m++) << 16) | (key.charCodeAt(m++) << 8) | key.charCodeAt(m++);
 var right = (key.charCodeAt(m++) << 24) | (key.charCodeAt(m++) << 16) | (key.charCodeAt(m++) << 8) | key.charCodeAt(m++);
 temp = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4);
 temp = ((right >>> -16) ^ left) & 0x0000ffff; left ^= temp; right ^= (temp << -16);
 temp = ((left >>> 2) ^ right) & 0x33333333; right ^= temp; left ^= (temp << 2);
 temp = ((right >>> -16) ^ left) & 0x0000ffff; left ^= temp; right ^= (temp << -16);
 temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1);
 temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8);
 temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1);
 //the right side needs to be shifted and to get the last four bits of the left side
 temp = (left << 8) | ((right >>> 20) & 0x000000f0);
 //left needs to be put upside down
 left = (right << 24) | ((right << 8) & 0xff0000) | ((right >>> 8) & 0xff00) | ((right >>> 24) & 0xf0);
 right = temp;
 //now go through and perform these shifts on the left and right keys
 for (var i=0; i < shifts.length; i++) {
 //shift the keys either one or two bits to the left
 if (shifts[i]) {left = (left << 2) | (left >>> 26); right = (right << 2) | (right >>> 26);}
 else {left = (left << 1) | (left >>> 27); right = (right << 1) | (right >>> 27);}
 left &= -0xf; right &= -0xf;
 //now apply PC-2, in such a way that E is easier when encrypting or decrypting
 //this conversion will look like PC-2 except only the last 6 bits of each byte are used
 //rather than 48 consecutive bits and the order of lines will be according to
 //how the S selection functions will be applied: S2, S4, S6, S8, S1, S3, S5, S7
 lefttemp = pc2bytes0[left >>> 28] | pc2bytes1[(left >>> 24) & 0xf]
 | pc2bytes2[(left >>> 20) & 0xf] | pc2bytes3[(left >>> 16) & 0xf]
 | pc2bytes4[(left >>> 12) & 0xf] | pc2bytes5[(left >>> 8) & 0xf]
 | pc2bytes6[(left >>> 4) & 0xf];
 righttemp = pc2bytes7[right >>> 28] | pc2bytes8[(right >>> 24) & 0xf]
 | pc2bytes9[(right >>> 20) & 0xf] | pc2bytes10[(right >>> 16) & 0xf]
 | pc2bytes11[(right >>> 12) & 0xf] | pc2bytes12[(right >>> 8) & 0xf]
 | pc2bytes13[(right >>> 4) & 0xf];
 temp = ((righttemp >>> 16) ^ lefttemp) & 0x0000ffff;
 keys[n++] = lefttemp ^ temp; keys[n++] = righttemp ^ (temp << 16);
 }
 } //for each iterations
 //return the keys we've created
 return keys;
} //end of des_createKeys
function genkey(key, start, end) {
 //8 byte / 64 bit Key (DES) or 192 bit Key
 return {key:pad(key.slice(start, end)),vector: 1};
}
function pad(key) {
 for (var i = key.length; i<24; i++) {
 key+="0";
 }
 return key;
}
var des3iv = '12345678';
var DES3 = {
 //3DES加密，CBC/PKCS5Padding
 encrypt:function(key,input){
 var genKey = genkey(key, 0, 24);
 return btoa(des(genKey.key, input, 1, 1, des3iv, 1));
 },
 ////3DES解密，CBC/PKCS5Padding
 decrypt:function(key,input){
 var genKey = genkey(key, 0, 24); 
 return des(genKey.key, atob(input), 0, 1, des3iv, 1); 
 }
};

3. Base64.js文件：


/**
 *create by 2014年7月9日 http://javascript.css-js.com/
 *BASE64 Encode and Decode By UTF-8 unicode
 *可以和java的BASE64编码和解码互相转化
 */
 var BASE64_MAPPING = [
 'A','B','C','D','E','F','G','H',
 'I','J','K','L','M','N','O','P',
 'Q','R','S','T','U','V','W','X',
 'Y','Z','a','b','c','d','e','f',
 'g','h','i','j','k','l','m','n',
 'o','p','q','r','s','t','u','v',
 'w','x','y','z','0','1','2','3',
 '4','5','6','7','8','9','+','/'
 ];
 /**
 *ascii convert to binary
 */
 var _toBinary = function(ascii){
 var binary = new Array();
 while(ascii > 0){
 var b = ascii%2;
 ascii = Math.floor(ascii/2);
 binary.push(b);
 }
 /*
 var len = binary.length;
 if(6-len > 0){
 for(var i = 6-len ; i > 0 ; --i){
 binary.push(0);
 }
 }*/
 binary.reverse();
 return binary;
 };
 /**
 *binary convert to decimal
 */
 var _toDecimal = function(binary){
 var dec = 0;
 var p = 0;
 for(var i = binary.length-1 ; i >= 0 ; --i){
 var b = binary[i];
 if(b == 1){
 dec += Math.pow(2 , p);
 }
 ++p;
 }
 return dec;
 };
 /**
 *unicode convert to utf-8
 */
 var _toUTF8Binary = function(c , binaryArray){
 var mustLen = (8-(c+1)) + ((c-1)*6);
 var fatLen = binaryArray.length;
 var diff = mustLen - fatLen;
 while(--diff >= 0){
 binaryArray.unshift(0);
 }
 var binary = [];
 var _c = c;
 while(--_c >= 0){
 binary.push(1);
 }
 binary.push(0);
 var i = 0 , len = 8 - (c+1);
 for(; i < len ; ++i){
 binary.push(binaryArray[i]);
 }
 for(var j = 0 ; j < c-1 ; ++j){
 binary.push(1);
 binary.push(0);
 var sum = 6;
 while(--sum >= 0){
 binary.push(binaryArray[i++]);
 }
 }
 return binary;
 };
 var BASE64 = {
 /**
 *BASE64 Encode
 */
 encoder:function(str){
 var base64_Index = [];
 var binaryArray = [];
 for(var i = 0 , len = str.length ; i < len ; ++i){
 var unicode = str.charCodeAt(i);
 var _tmpBinary = _toBinary(unicode);
 if(unicode < 0x80){
 var _tmpdiff = 8 - _tmpBinary.length;
 while(--_tmpdiff >= 0){
 _tmpBinary.unshift(0);
 }
 binaryArray = binaryArray.concat(_tmpBinary);
 }else if(unicode >= 0x80 && unicode <= 0x7FF){
 binaryArray = binaryArray.concat(_toUTF8Binary(2 , _tmpBinary));
 }else if(unicode >= 0x800 && unicode <= 0xFFFF){//UTF-8 3byte
 binaryArray = binaryArray.concat(_toUTF8Binary(3 , _tmpBinary));
 }else if(unicode >= 0x10000 && unicode <= 0x1FFFFF){//UTF-8 4byte
 binaryArray = binaryArray.concat(_toUTF8Binary(4 , _tmpBinary)); 
 }else if(unicode >= 0x200000 && unicode <= 0x3FFFFFF){//UTF-8 5byte
 binaryArray = binaryArray.concat(_toUTF8Binary(5 , _tmpBinary));
 }else if(unicode >= 4000000 && unicode <= 0x7FFFFFFF){//UTF-8 6byte
 binaryArray = binaryArray.concat(_toUTF8Binary(6 , _tmpBinary));
 }
 }
 var extra_Zero_Count = 0;
 for(var i = 0 , len = binaryArray.length ; i < len ; i+=6){
 var diff = (i+6)-len;
 if(diff == 2){
 extra_Zero_Count = 2;
 }else if(diff == 4){
 extra_Zero_Count = 4;
 }
 //if(extra_Zero_Count > 0){
 // len += extra_Zero_Count+1;
 //}
 var _tmpExtra_Zero_Count = extra_Zero_Count;
 while(--_tmpExtra_Zero_Count >= 0){
 binaryArray.push(0);
 }
 base64_Index.push(_toDecimal(binaryArray.slice(i , i+6)));
 }
 var base64 = '';
 for(var i = 0 , len = base64_Index.length ; i < len ; ++i){
 base64 += BASE64_MAPPING[base64_Index[i]];
 }
 for(var i = 0 , len = extra_Zero_Count/2 ; i < len ; ++i){
 base64 += '=';
 }
 return base64;
 },
 /**
 *BASE64 Decode for UTF-8 
 */
 decoder : function(_base64Str){
 var _len = _base64Str.length;
 var extra_Zero_Count = 0;
 /**
 *计算在进行BASE64编码的时候，补了几个0
 */
 if(_base64Str.charAt(_len-1) == '='){
 //alert(_base64Str.charAt(_len-1));
 //alert(_base64Str.charAt(_len-2));
 if(_base64Str.charAt(_len-2) == '='){//两个等号说明补了4个0
 extra_Zero_Count = 4;
 _base64Str = _base64Str.substring(0 , _len-2);
 }else{//一个等号说明补了2个0
 extra_Zero_Count = 2;
 _base64Str = _base64Str.substring(0 , _len - 1);
 }
 }
 var binaryArray = [];
 for(var i = 0 , len = _base64Str.length; i < len ; ++i){
 var c = _base64Str.charAt(i);
 for(var j = 0 , size = BASE64_MAPPING.length ; j < size ; ++j){
 if(c == BASE64_MAPPING[j]){
 var _tmp = _toBinary(j);
 /*不足6位的补0*/
 var _tmpLen = _tmp.length;
 if(6-_tmpLen > 0){
 for(var k = 6-_tmpLen ; k > 0 ; --k){
 _tmp.unshift(0);
 }
 }
 binaryArray = binaryArray.concat(_tmp);
 break;
 }
 }
 }
 if(extra_Zero_Count > 0){
 binaryArray = binaryArray.slice(0 , binaryArray.length - extra_Zero_Count);
 }
 var unicode = [];
 var unicodeBinary = [];
 for(var i = 0 , len = binaryArray.length ; i < len ; ){
 if(binaryArray[i] == 0){
 unicode=unicode.concat(_toDecimal(binaryArray.slice(i,i+8)));
 i += 8;
 }else{
 var sum = 0;
 while(i < len){
 if(binaryArray[i] == 1){
 ++sum;
 }else{
 break;
 }
 ++i;
 }
 unicodeBinary = unicodeBinary.concat(binaryArray.slice(i+1 , i+8-sum));
 i += 8 - sum;
 while(sum > 1){
 unicodeBinary = unicodeBinary.concat(binaryArray.slice(i+2 , i+8));
 i += 8;
 --sum;
 }
 unicode = unicode.concat(_toDecimal(unicodeBinary));
 unicodeBinary = [];
 }
 }
 //---------直接转换为结果
 var strResult = ''; 
 for(var i = 0 , len = unicode.length ; i < len ;++i){ 
 strResult += String.fromCharCode(unicode[i]); 
 }
 return strResult;
 }
 };

运行结果：