base64

Provides full cross browser (and legacy browser) support for Base64 Encoding and Decoding true (not just merican) UTF-8 charset strings in Javascript. Will work with Base64 encoding and the UTF-8 charset on the .NET platform.

It's a complete wonder that we in 2020 still don't have a decent international charset support for a standard nearly 30 years old, used by the majority of the world.

base64.encode in javascript

var encodedString = base64.encode(decodedString)

OR

var encodedString = btoa(decodedString)

base64.decode in javascript

var decodedString = base64.decode(encodedString)

OR

var decodedString = atob(encodedString)

encode in C#

var encodedString = Convert.ToBase64String(
    Encoding.UTF8.GetBytes(
        HttpUtility.UrlEncode("Decoded string")))

decode in C#

var decodedString = HttpUtility.UrlDecode(
    Encoding.UTF8.GetString(
        Convert.FromBase64String("RW5jb2RlZCUyMHN0cmluZw==")))

C# Extension for string

public static class StringExtensions
{
    public static string Base64Encode(this string str) =>
        Convert.ToBase64String(Encoding.UTF8.GetBytes(HttpUtility.UrlEncode(str ?? string.Empty)));

    public static string Base64Decode(this string str) =>
        HttpUtility.UrlDecode(Encoding.UTF8.GetString(Convert.FromBase64String(str)));
}

Usage

var encodedString = "Decoded string".Base64Encode()

var decodedString = "RW5jb2RlZCUyMHN0cmluZw==".Base64Decode()