/** *create by 2014年7月9日 *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','+','https://www.jb51.net/' ]; /** *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：
PS：关于加密解密感兴趣的朋友还可以参考本站在线工具：
在线编码转换工具(utf-8/utf-32/Punycode/Base64)：
在线MD5/hash/SHA-1/SHA-2/SHA-256/SHA-512/SHA-3/RIPEMD-160加密工具：