【BASE64】JS 实现BASE64_ENCODE和BASE64_DECODE(实例代码)-ENCODE

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JS 实现BASE64_ENCODE和BASE64_DECODE(实例代码)

<script language='javascript'>

function utf16to8(str) {
     var out, i, len, c;

     out="";
     len=str.length;
     for(i=0; i < len; i++) {
         c=str.charCodeAt(i);
         if ((c >=0x0001) && (c <=0x007F)) {
             out +=str.charAt(i);
         } else if (c > 0x07FF) {
             out +=String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
             out +=String.fromCharCode(0x80 | ((c >>   6) & 0x3F));
             out +=String.fromCharCode(0x80 | ((c >>   0) & 0x3F));
         } else {
             out +=String.fromCharCode(0xC0 | ((c >>   6) & 0x1F));
             out +=String.fromCharCode(0x80 | ((c >>   0) & 0x3F));
         }
     }
     return out;
}

function utf8to16(str) {
     var out, i, len, c;
     var char2, char3;

     out="";
     len=str.length;
     i=0;
     while(i < len) {
         c=str.charCodeAt(i++);
         switch(c >> 4)
         {
           case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
             // 0xxxxxxx
             out +=str.charAt(i-1);
             break;
           case 12: case 13:
             // 110x xxxx    10xx xxxx
             char2=str.charCodeAt(i++);
             out +=String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
             break;
           case 14:
             // 1110 xxxx   10xx xxxx   10xx xxxx
             char2=str.charCodeAt(i++);
             char3=str.charCodeAt(i++);
             out +=String.fromCharCode(((c & 0x0F) << 12) |
                                            ((char2 & 0x3F) << 6) |
                                            ((char3 & 0x3F) << 0));
             break;
         }
     }

     return out;
}

var base64EncodeChars="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var base64DecodeChars=new Array(
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
     52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
     -1,   0,   1,   2,   3,   4,   5,   6,   7,   8,   9, 10, 11, 12, 13, 14,
     15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
     -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
     41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);

function base64encode(str) {
     var out, i, len;
     var c1, c2, c3;

     len=str.length;
     i=0;
     out="";
     while(i < len) {
         c1=str.charCodeAt(i++) & 0xff;
         if(i==len)
         {
             out +=base64EncodeChars.charAt(c1 >> 2);
             out +=base64EncodeChars.charAt((c1 & 0x3) << 4);
             out +="==";
             break;
         }
         c2=str.charCodeAt(i++);
         if(i==len)
         {
             out +=base64EncodeChars.charAt(c1 >> 2);
             out +=base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
             out +=base64EncodeChars.charAt((c2 & 0xF) << 2);
             out +="=";
             break;
         }
         c3=str.charCodeAt(i++);
         out +=base64EncodeChars.charAt(c1 >> 2);
         out +=base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
         out +=base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6));
         out +=base64EncodeChars.charAt(c3 & 0x3F);
     }
     return out;
}

function base64decode(str) {
     var c1, c2, c3, c4;
     var i, len, out;

     len=str.length;
     i=0;
     out="";
     while(i < len) {
        
         do {
             c1=base64DecodeChars[str.charCodeAt(i++) & 0xff];
         } while(i < len && c1==-1);
         if(c1==-1)
             break;

        
         do {
             c2=base64DecodeChars[str.charCodeAt(i++) & 0xff];
         } while(i < len && c2==-1);
         if(c2==-1)
             break;

         out +=String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));

        
         do {
             c3=str.charCodeAt(i++) & 0xff;
             if(c3==61)
                 return out;
             c3=base64DecodeChars[c3];
         } while(i < len && c3==-1);
         if(c3==-1)
             break;

         out +=String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));

        
         do {
             c4=str.charCodeAt(i++) & 0xff;
             if(c4==61)
                 return out;
             c4=base64DecodeChars[c4];
         } while(i < len && c4==-1);
         if(c4==-1)
             break;
         out +=String.fromCharCode(((c3 & 0x03) << 6) | c4);
     }
     return out;
}
//input base64 encode
function strdecode(str){
         return utf8to16(base64decode(str));
}

关于JS 实现BASE64_ENCODE和BASE64_DECODE(实例代码)的用户互动如下：

　　相关问题：在Java中如何进行BASE64编码和解码

　　答：import sun.misc.BASE64Encoder; import sun.misc.BASE64Decoder; // 将 s 进行 BASE64 编码 public static String getBASE64(String s) { if (s == null) return null; return (new sun.misc.BASE64Encoder()).encode( s.getBytes() ); } // 将... >>详细

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　　答：就是可以解的加密方式 base64_encode(); base64_decode(); 因为一些字符，如链接get方式， 浏览器不可以带很多特殊字符，导致php获取不到正确的信息，用加密一下就好多了， 不过注意大小写。 >>详细

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　　答：function Base64() { // private property _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; // public method for encoding this.encode = function (input) { var output = ""; var chr1, chr2, chr3, enc1, ... >>详细