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
这是一个atob()和btoa() JavaScript内置函数的现场演示:
<!DOCTYPE html>
<html>
<head>
<style>
textarea{
width:30%;
height:100px;
}
</style>
<script>
// encode string to base64
function encode()
{
var txt = document.getElementById("txt1").value;
var result = btoa(txt);
document.getElementById("txt2").value = result;
}
// decode base64 back to original string
function decode()
{
var txt = document.getElementById("txt3").value;
var result = atob(txt);
document.getElementById("txt4").value = result;
}
</script>
</head>
<body>
<div>
<textarea id="txt1">Some text to decode
</textarea>
</div>
<div>
<input type="button" id="btnencode" value="Encode" onClick="encode()"/>
</div>
<div>
<textarea id="txt2">
</textarea>
</div>
<br/>
<div>
<textarea id="txt3">U29tZSB0ZXh0IHRvIGRlY29kZQ==
</textarea>
</div>
<div>
<input type="button" id="btndecode" value="Decode" onClick="decode()"/>
</div>
<div>
<textarea id="txt4">
</textarea>
</div>
</body>
</html>
其他回答
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=");
Internet Explorer 10+
// Define the string
var string = 'Hello World!';
// Encode the String
var encodedString = btoa(string);
console.log(encodedString); // Outputs: "SGVsbG8gV29ybGQh"
// Decode the String
var decodedString = atob(encodedString);
console.log(decodedString); // Outputs: "Hello World!"
跨浏览器
// Create Base64 Object
var Base64={_keyStr:"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",encode:function(e){var t="";var n,r,i,s,o,u,a;var f=0;e=Base64._utf8_encode(e);while(f<e.length){n=e.charCodeAt(f++);r=e.charCodeAt(f++);i=e.charCodeAt(f++);s=n>>2;o=(n&3)<<4|r>>4;u=(r&15)<<2|i>>6;a=i&63;if(isNaN(r)){u=a=64}else if(isNaN(i)){a=64}t=t+this._keyStr.charAt(s)+this._keyStr.charAt(o)+this._keyStr.charAt(u)+this._keyStr.charAt(a)}return t},decode:function(e){var t="";var n,r,i;var s,o,u,a;var f=0;e=e.replace(/[^A-Za-z0-9\+\/\=]/g,"");while(f<e.length){s=this._keyStr.indexOf(e.charAt(f++));o=this._keyStr.indexOf(e.charAt(f++));u=this._keyStr.indexOf(e.charAt(f++));a=this._keyStr.indexOf(e.charAt(f++));n=s<<2|o>>4;r=(o&15)<<4|u>>2;i=(u&3)<<6|a;t=t+String.fromCharCode(n);if(u!=64){t=t+String.fromCharCode(r)}if(a!=64){t=t+String.fromCharCode(i)}}t=Base64._utf8_decode(t);return t},_utf8_encode:function(e){e=e.replace(/\r\n/g,"\n");var t="";for(var n=0;n<e.length;n++){var r=e.charCodeAt(n);if(r<128){t+=String.fromCharCode(r)}else if(r>127&&r<2048){t+=String.fromCharCode(r>>6|192);t+=String.fromCharCode(r&63|128)}else{t+=String.fromCharCode(r>>12|224);t+=String.fromCharCode(r>>6&63|128);t+=String.fromCharCode(r&63|128)}}return t},_utf8_decode:function(e){var t="";var n=0;var r=c1=c2=0;while(n<e.length){r=e.charCodeAt(n);if(r<128){t+=String.fromCharCode(r);n++}else if(r>191&&r<224){c2=e.charCodeAt(n+1);t+=String.fromCharCode((r&31)<<6|c2&63);n+=2}else{c2=e.charCodeAt(n+1);c3=e.charCodeAt(n+2);t+=String.fromCharCode((r&15)<<12|(c2&63)<<6|c3&63);n+=3}}return t}}
// Define the string
var string = 'Hello World!';
// Encode the String
var encodedString = Base64.encode(string);
console.log(encodedString); // Outputs: "SGVsbG8gV29ybGQh"
// Decode the String
var decodedString = Base64.decode(encodedString);
console.log(decodedString); // Outputs: "Hello World!"
js小提琴
用node . js
下面是在Node.js中如何将普通文本编码为base64:
//Buffer() requires a number, array or string as the first parameter, and an optional encoding type as the second parameter.
// The default is "utf8". Possible encoding types are "ascii", "utf8", "ucs2", "base64", "binary", and "hex"
var b = Buffer.from('JavaScript');
// If we don't use toString(), JavaScript assumes we want to convert the object to utf8.
// We can make it convert to other formats by passing the encoding type to toString().
var s = b.toString('base64');
下面是解码base64编码字符串的方法:
var b = new Buffer('SmF2YVNjcmlwdA==', 'base64')
var s = b.toString();
. js和
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)
安装angular-base64
<script src="bower_components/angular-base64/angular-base64.js"></script>
angular
.module('myApp', ['base64'])
.controller('myController', [
'$base64', '$scope',
function($base64, $scope) {
$scope.encoded = $base64.encode('a string');
$scope.decoded = $base64.decode('YSBzdHJpbmc=');
}]);
基本上，我只是稍微清理了一下原始代码，这样JSLint就不会抱怨太多了，而且我把注释中标记为私有的方法实际上变成了私有的。我还添加了我在自己的项目中需要的两个方法，即decodeToHex和encodeFromHex。
代码:
var Base64 = (function() {
"use strict";
var _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
var _utf8_encode = function (string) {
var utftext = "", c, n;
string = string.replace(/\r\n/g,"\n");
for (n = 0; n < string.length; n++) {
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;
};
var _utf8_decode = function (utftext) {
var string = "", i = 0, c = 0, c1 = 0, c2 = 0;
while ( i < utftext.length ) {
c = utftext.charCodeAt(i);
if (c < 128) {
string += String.fromCharCode(c);
i++;
} else if((c > 191) && (c < 224)) {
c1 = utftext.charCodeAt(i+1);
string += String.fromCharCode(((c & 31) << 6) | (c1 & 63));
i += 2;
} else {
c1 = utftext.charCodeAt(i+1);
c2 = utftext.charCodeAt(i+2);
string += String.fromCharCode(((c & 15) << 12) | ((c1 & 63) << 6) | (c2 & 63));
i += 3;
}
}
return string;
};
var _hexEncode = function(input) {
var output = '', i;
for(i = 0; i < input.length; i++) {
output += input.charCodeAt(i).toString(16);
}
return output;
};
var _hexDecode = function(input) {
var output = '', i;
if(input.length % 2 > 0) {
input = '0' + input;
}
for(i = 0; i < input.length; i = i + 2) {
output += String.fromCharCode(parseInt(input.charAt(i) + input.charAt(i + 1), 16));
}
return output;
};
var encode = function (input) {
var output = "", chr1, chr2, chr3, enc1, enc2, enc3, enc4, 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 += _keyStr.charAt(enc1);
output += _keyStr.charAt(enc2);
output += _keyStr.charAt(enc3);
output += _keyStr.charAt(enc4);
}
return output;
};
var decode = function (input) {
var output = "", chr1, chr2, chr3, enc1, enc2, enc3, enc4, 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 += String.fromCharCode(chr1);
if (enc3 !== 64) {
output += String.fromCharCode(chr2);
}
if (enc4 !== 64) {
output += String.fromCharCode(chr3);
}
}
return _utf8_decode(output);
};
var decodeToHex = function(input) {
return _hexEncode(decode(input));
};
var encodeFromHex = function(input) {
return encode(_hexDecode(input));
};
return {
'encode': encode,
'decode': decode,
'decodeToHex': decodeToHex,
'encodeFromHex': encodeFromHex
};
}());
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);
这是一个helper funktion来编码到base64url:
base64url (s) {
var to64url = btao(s);
// Replace non-url compatible chars with base64url standard chars and remove leading =
return to64url.replace(/\+/g, '_').replace(/\//g, '-').replace(/=+$/g, '');
}
