如何在JavaScript中将字符串编码为Base64 ?

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

我宁愿使用CryptoJS中的Base64编码/解码方法，这是使用最佳实践和模式在JavaScript中实现的最流行的标准和安全加密算法库。

2013-11-17 07:05:24

其他回答

您可以使用btoa()和atob()来转换base64编码。

关于这些函数接受/返回什么，评论中似乎有一些混淆，所以…

btoa() accepts a “string” where each character represents an 8-bit byte – if you pass a string containing characters that can’t be represented in 8 bits, it will probably break. This isn’t a problem if you’re actually treating the string as a byte array, but if you’re trying to do something else then you’ll have to encode it first. atob() returns a “string” where each character represents an 8-bit byte – that is, its value will be between 0 and 0xff. This does not mean it’s ASCII – presumably if you’re using this function at all, you expect to be working with binary data and not text.

参见:

如何使用Javascript和XMLHttpRequest加载二进制图像数据?

这里的大多数评论都过时了。您可能同时使用btoa()和atob()，除非您支持非常过时的浏览器。

检查:

https://caniuse.com/?search=atob https://caniuse.com/?search=btoa

2008-10-29 15:31:03

下面是@user850789的AngularJS Factory版本:

'use strict';

var ProjectNameBase64Factory = angular.module('project_name.factories.base64', []);

ProjectNameBase64Factory.factory('Base64', function () {
    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 +
                         Base64._keyStr.charAt(enc1) + Base64._keyStr.charAt(enc2) +
                         Base64._keyStr.charAt(enc3) + Base64._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 = Base64._keyStr.indexOf(input.charAt(i++));
                enc2 = Base64._keyStr.indexOf(input.charAt(i++));
                enc3 = Base64._keyStr.indexOf(input.charAt(i++));
                enc4 = Base64._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 = 0, c2 = 0, c3 = 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;
        }
    };
    return Base64;
});

2014-05-25 04:27:29

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);

2013-08-29 14:10:34

JavaScript没有btoa中间步骤(没有库)

在问题标题中你写的是字符串转换，但在问题中你谈论的是二进制数据(图片)，所以这里有一个函数，从PNG图片二进制数据开始进行适当的转换(详细信息和反转转换在这里)。

2020-07-27 11:43:48

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

2022-03-30 07:10:42

如何在JavaScript中将字符串编码为Base64 ?

推荐文章

最新文章

标签