我有一个PHP脚本，可以将PNG图像编码为Base64字符串。
我想用JavaScript做同样的事情。我知道如何打开文件，但我不知道如何进行编码。我不习惯使用二进制数据。
当前回答
请注意，这不适用于原始的Unicode字符串!请参阅这里的Unicode部分。
编码语法
var encodedData = window.btoa（stringToEncode）;
解码语法
var decodedData = window.atob（encodedData）;
其他回答
从这里开始:
/**
*
* Base64 encode / decode
* http://www.webtoolkit.info/
*
**/
var Base64 = {
// private property
_keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
// public method for encoding
encode : function (input) {
var output = "";
var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
var i = 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;
} else if (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 decoding
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 = 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");
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
_utf8_decode : function (utftext) {
var string = "";
var i = 0;
var c = c1 = 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;
}
}
此外，搜索“JavaScript base64 encoding”会出现许多其他选项，上面是第一个。
您可以使用btoa(从Base64)和atob(从Base64)。
对于ie9及以下版本，请尝试jquery-base64插件:
$.base64.encode("this is a test");
$.base64.decode("dGhpcyBpcyBhIHRlc3Q=");
如果有人想在Typescript中将一个字符串编码为base64
我调整了Peter Mortensen的答案并添加了类型(在需要的地方)
const Base64 = {
_keyStr: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
// added type string to input
encode: function(input: string) {
let output = "";
let chr1, chr2, chr3, enc1, enc2, enc3, enc4;
let i = 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;
} else if (isNaN(chr3)) {
enc4 = 64;
}
output = output + this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) + this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
}
return output;
},
// added type string to input
_utf8_encode: function(input: string) {
input= input.replace(/\r\n/g, "\n");
let utftext = "";
for (let n = 0; n < input.length; n++) {
let c = input.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;
},
}
// function that consumes that Base64.encode function
const encode = ( cipher : string) => {
const encodedString: string = Base64.encode(cipher)
return encodedString;
}
console.log(encode('Hello World!'))
JSFIDDLE 链接
您可以在浏览器中使用btoa()/atob()，但需要一些改进，如https://base64tool.com/uncaught-domexception-btoa-on-window/和https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/btoa所述的UTF字符串支持!
如果您正在使用Dojo。它为我们提供了编码或解码为Base64的直接方法。
试试这个:
使用dojox.encoding.base64对字节数组进行编码:
var str = dojox.encoding.base64.encode(myByteArray);
解码一个base64编码的字符串:
var bytes = dojox.encoding.base64.decode(str);
