微信小程序字符串base64转码和解码

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function Base64() {

// private property

let _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

var _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

var _utf8_decode = function (utftext) {

var string = "";

let i = 0;

let c = 0;

let c1 = 0;

let 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;

}

}

修改他人的代码，只为方便使用

使用方式

var base = new Base64();//保证引入路径真确

//1.加密

var str = '124中文内容';

var result = base.encode(str);

//document.write(result);

//2.解密

var result2 = base.decode(result);

document.write(result2);