場景

這幾天使用PHP向前端傳值的時候，遇到一個問題，要將程式碼傳過去賦值。如果使用urlencode()和urldecode()函式，就會出現js無法解碼的情況，因為php和js的相關函式演算法不一致。於是準備使用通用的base64加密解密。

javascript base64 加密解密

  下方是base64用javascript寫出來的函式和方法。

  1 //1.加密解密方法使用：
  2 
  3 //1.加密  
  4 var str = '124中文內容';  
  5 var base = new Base64();  
  6 var result = base.encode(str);  
 
  7 document.write(result);  
  8 
  9 //2.解密  
 10 var result2 = base.decode(result);  
 11 document.write(result2);  
 12 //2.加密、解密演算法封裝：
 13 
 14 function Base64() {  
 15 
 16     // private property  
 17     _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";  
 18
 
 
 19     // public method for encoding  
 20     this.encode = function (input) {  
 21         var output = "";  
 22         var chr1, chr2, chr3, enc1, enc2, enc3, enc4;  
 23         var i = 0;  
 24         input = _utf8_encode(input);  
 25         while (i < input.length) {  
 26             chr1 = input.charCodeAt(i++);  
 
 27             chr2 = input.charCodeAt(i++);  
 28             chr3 = input.charCodeAt(i++);  
 29             enc1 = chr1 >> 2;  
 30             enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);  
 31             enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);  
 32             enc4 = chr3 & 63;  
 33             if (isNaN(chr2)) {  
 34                 enc3 = enc4 = 64;  
 35             } else if (isNaN(chr3)) {  
 36                 enc4 = 64;  
 37             }  
 38             output = output +  
 39             _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +  
 40             _keyStr.charAt(enc3) + _keyStr.charAt(enc4);  
 41         }  
 42         return output;  
 43     }  
 44 
 45     // public method for decoding  
 46     this.decode = function (input) {  
 47         var output = "";  
 48         var chr1, chr2, chr3;  
 49         var enc1, enc2, enc3, enc4;  
 50         var i = 0;  
 51         input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");  
 52         while (i < input.length) {  
 53             enc1 = _keyStr.indexOf(input.charAt(i++));  
 54             enc2 = _keyStr.indexOf(input.charAt(i++));  
 55             enc3 = _keyStr.indexOf(input.charAt(i++));  
 56             enc4 = _keyStr.indexOf(input.charAt(i++));  
 57             chr1 = (enc1 << 2) | (enc2 >> 4);  
 58             chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);  
 59             chr3 = ((enc3 & 3) << 6) | enc4;  
 60             output = output + String.fromCharCode(chr1);  
 61             if (enc3 != 64) {  
 62                 output = output + String.fromCharCode(chr2);  
 63             }  
 64             if (enc4 != 64) {  
 65                 output = output + String.fromCharCode(chr3);  
 66             }  
 67         }  
 68         output = _utf8_decode(output);  
 69         return output;  
 70     }  
 71 
 72     // private method for UTF-8 encoding  
 73     _utf8_encode = function (string) {  
 74         string = string.replace(/\r\n/g,"\n");  
 75         var utftext = "";  
 76         for (var n = 0; n < string.length; n++) {  
 77             var c = string.charCodeAt(n);  
 78             if (c < 128) {  
 79                 utftext += String.fromCharCode(c);  
 80             } else if((c > 127) && (c < 2048)) {  
 81                 utftext += String.fromCharCode((c >> 6) | 192);  
 82                 utftext += String.fromCharCode((c & 63) | 128);  
 83             } else {  
 84                 utftext += String.fromCharCode((c >> 12) | 224);  
 85                 utftext += String.fromCharCode(((c >> 6) & 63) | 128);  
 86                 utftext += String.fromCharCode((c & 63) | 128);  
 87             }  
 88 
 89         }  
 90         return utftext;  
 91     }  
 92 
 93     // private method for UTF-8 decoding  
 94     _utf8_decode = function (utftext) {  
 95         var string = "";  
 96         var i = 0;  
 97         var c = c1 = c2 = 0;  
 98         while ( i < utftext.length ) {  
 99             c = utftext.charCodeAt(i);  
100             if (c < 128) {  
101                 string += String.fromCharCode(c);  
102                 i++;  
103             } else if((c > 191) && (c < 224)) {  
104                 c2 = utftext.charCodeAt(i+1);  
105                 string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));  
106                 i += 2;  
107             } else {  
108                 c2 = utftext.charCodeAt(i+1);  
109                 c3 = utftext.charCodeAt(i+2);  
110                 string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));  
111                 i += 3;  
112             }  
113         }  
114         return string;  
115     }  
116 }

完全引用自

---------------------
作者：夜之寐
來源：CSDN
原文：https://blog.csdn.net/u012369749/article/details/73784897
版權宣告：本文為博主原創文章，轉載請附上博文連結！