JS字符串转base64格式
varBase64 = {
// private property_keyStr: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
// public method for encodingencode:function(input) {
varoutput = "";
var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
vari = 0;
input = Base64._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;
} elseif (isNaN(chr3)) {
enc4 = 64;
}
output = output +this._keyStr.charAt(enc1) +this._keyStr.charAt(enc2) +this._keyStr.charAt(enc3) +this._keyStr.charAt(enc4);
}
return output;
},
// public method for decodingdecode:function(input) {
varoutput = "";
var chr1, chr2, chr3;
var enc1, enc2, enc3, enc4;
vari = 0;
input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
while(i < input.length) {
enc1 =this._keyStr.indexOf(input.charAt(i++));
enc2 =this._keyStr.indexOf(input.charAt(i++));
enc3 =this._keyStr.indexOf(input.charAt(i++));
enc4 =this._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 = Base64._utf8_decode(output);
return output;
},
// private method for UTF-8 encoding_utf8_encode:function(string) {
string = string.replace(/\r\n/g, "\n");
varutftext = "";
for(varn = 0; n < string.length; n++) {
varc = string.charCodeAt(n);
if(c < 128) {
utftext += String.fromCharCode(c);
} elseif((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) {
varstring = "";
vari = 0;
varc = c1 = c2 = 0;
while(i < utftext.length) {
c = utftext.charCodeAt(i);
if(c < 128) {
string += String.fromCharCode(c);
i++;
} elseif((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;
}
}
使用方法
Base64.encode("www.johnz.co")// 编码Base64.decode("d3d3LmpvaG56LmNv")//解码
Base64编码说明 Base64编码要求把3个8位字节（3*8=24）转化为4个6位的字节（4*6=24），之后在6位的前面补两个0，形成8位一个字节的形式。 如果剩下的字符不足3个字节，则用0填充，输出字符使用'='，因此编码后输出的文本末尾可能会出现1或2个'='。
为了保证所输出的编码位可读字符，Base64制定了一个编码表，以便进行统一转换。编码表的大小为2^6=64，这也是Base64名称的由来。
Base64编码表
码值字符 码值字符 码值字符 码值字符
0A16Q32g48w
1B17R33h49x
2C18S34i50y
3D19T35j51z
4E20U36k520
5F21V37l531
6G22W38m542
7H23X39n553
8I24Y40o564
9J25Z41p575
10K26a42q586
11L27b43r597
12M28c44s608
13N29d45t619
14O30e46u62+
15P31f47v63/
通过本工具可以对代码进行Base64加密或者解密。Base64是网络上最常见的用于传输8Bit字节代码的编码方式之一。
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