[杂七杂八] Javascript实现base64的加密解密

  这几天使用PHP向前端传值的时候，遇到一个问题，要将代码传过去赋值。如果使用urlencode()和urldecode()函数，就会出现js无法解码的情况，因为php和js的相关函数算法不一致。于是准备使用通用的base64加密解密。

base64 加密解密

  下方是base64用javascript写出来的函数和方法。

//1.加密解密方法使用：//1.加密  var str = '124中文内容';  var base = new Base64();  var result = base.encode(str);  //document.write(result);  //2.解密  var result2 = base.decode(result);  document.write(result2);  //2.加密、解密算法封装：function Base64() {      // private property      _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";      // public method for encoding      this.encode = function (input) {          var output = "";          var chr1, chr2, chr3, enc1, enc2, enc3, enc4;          var i = 0;          input = _utf8_encode(input);          while (i < input.length) {              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);          }          return output;      }      // public method for decoding      this.decode = function (input) {          var output = "";          var chr1, chr2, chr3;          var enc1, enc2, enc3, enc4;          var i = 0;          input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");          while (i < input.length) {              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);              }          }          output = _utf8_decode(output);          return output;      }      // private method for UTF-8 encoding      _utf8_encode = function (string) {          string = string.replace(/\r\n/g,"\n");          var utftext = "";          for (var n = 0; n < string.length; n++) {              var c = string.charCodeAt(n);              if (c < 128) {                  utftext += String.fromCharCode(c);              } else if((c > 127) && (c < 2048)) {                  utftext += String.fromCharCode((c >> 6) | 192);                  utftext += String.fromCharCode((c & 63) | 128);              } else {                  utftext += String.fromCharCode((c >> 12) | 224);                  utftext += String.fromCharCode(((c >> 6) & 63) | 128);                  utftext += String.fromCharCode((c & 63) | 128);              }          }          return utftext;      }      // private method for UTF-8 decoding      _utf8_decode = function (utftext) {          var string = "";          var i = 0;          var c = c1 = c2 = 0;          while ( i < utftext.length ) {              c = utftext.charCodeAt(i);              if (c < 128) {                  string += String.fromCharCode(c);                  i++;              } else if((c > 191) && (c < 224)) {                  c2 = utftext.charCodeAt(i+1);                  string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));                  i += 2;              } else {                  c2 = utftext.charCodeAt(i+1);                  c3 = utftext.charCodeAt(i+2);                  string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));                  i += 3;              }          }          return string;      }  }