Javascript实现base64的加密解密方法 

  1 function Base64() {  
  2   // private property  
  3   _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";  
  4   // 公共编码方法 
  5   this.encode = function (input) {  
  6     var output = "";  
  7     var chr1, chr2, chr3, enc1, enc2, enc3, enc4;  
  8     var i = 0;  
  9     input = _utf8_encode(input);  
 10     while (i < input.length) {  
 11       chr1 = input.charCodeAt(i++);  
 12       chr2 = input.charCodeAt(i++);  
 13       chr3 = input.charCodeAt(i++);  
 14       enc1 = chr1 >> 2;  
 15       enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);  
 16       enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);  
 17       enc4 = chr3 & 63;  
 18       if (isNaN(chr2)) {  
 19           enc3 = enc4 = 64;  
 20       } else if (isNaN(chr3)) {  
 21           enc4 = 64;  
 22       }  
 23       output = output +  
 24       _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +  
 25       _keyStr.charAt(enc3) + _keyStr.charAt(enc4);  
 26     }  
 27     return output;  
 28   }  
 29 
 30   // 公共解码方法
 31   this.decode = function (input) {  
 32     var output = "";  
 33     var chr1, chr2, chr3;  
 34     var enc1, enc2, enc3, enc4;  
 35     var i = 0;  
 36     input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");  
 37     while (i < input.length) {  
 38       enc1 = _keyStr.indexOf(input.charAt(i++));  
 39       enc2 = _keyStr.indexOf(input.charAt(i++));  
 40       enc3 = _keyStr.indexOf(input.charAt(i++));  
 41       enc4 = _keyStr.indexOf(input.charAt(i++));  
 42       chr1 = (enc1 << 2) | (enc2 >> 4);  
 43       chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);  
 44       chr3 = ((enc3 & 3) << 6) | enc4;  
 45       output = output + String.fromCharCode(chr1);  
 46       if (enc3 != 64) {  
 47         output = output + String.fromCharCode(chr2);  
 48       }  
 49       if (enc4 != 64) {  
 50         output = output + String.fromCharCode(chr3);  
 51       }
 52     }  
 53     output = _utf8_decode(output);  
 54     return output;  
 55   }  
 56 
 57   // UTF-8编码的私有方法  
 58   _utf8_encode = function (string) {  
 59     string = string.replace(/\r\n/g,"\n");  
 60     var utftext = "";  
 61     for (var n = 0; n < string.length; n++) {  
 62       var c = string.charCodeAt(n);  
 63       if (c < 128) {  
 64         utftext += String.fromCharCode(c);  
 65       } else if((c > 127) && (c < 2048)) {  
 66         utftext += String.fromCharCode((c >> 6) | 192);  
 67         utftext += String.fromCharCode((c & 63) | 128);  
 68       } else {  
 69         utftext += String.fromCharCode((c >> 12) | 224);  
 70         utftext += String.fromCharCode(((c >> 6) & 63) | 128);  
 71         utftext += String.fromCharCode((c & 63) | 128);  
 72       }
 73     }  
 74     return utftext;  
 75   }  
 76 
 77   // UTF-8解码的私有方法  
 78   _utf8_decode = function (utftext) {  
 79     var string = "";  
 80     var i = 0;  
 81     var c = c1 = c2 = 0;  
 82     while ( i < utftext.length ) {  
 83       c = utftext.charCodeAt(i);  
 84       if (c < 128) {  
 85         string += String.fromCharCode(c);  
 86         i++;  
 87       } else if((c > 191) && (c < 224)) {  
 88         c2 = utftext.charCodeAt(i+1);  
 89         string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));  
 90         i += 2;  
 91       } else {  
 92         c2 = utftext.charCodeAt(i+1);  
 93         c3 = utftext.charCodeAt(i+2);  
 94         string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));  
 95         i += 3;  
 96       }  
 97     }  
 98     return string;  
 99   }  
100 }

加密解密方法使用：

1.加密

var str = '码云笔记mybj123';  
var base = new Base64();  
var result = base.encode(str);  
//document.write(result);
2. 解密

var result2 = base.decode(result);  
document.write(result2);

 

 
 
posted @ 2022-07-27 17:58  瑆箫  阅读(4343)  评论(0)  编辑  收藏  举报