JS Base64 encoding and decoding

Base64 It's a way of encoding , Any character can be （ Including binary character stream ） Convert to printable characters .

JavaScript

Defines two and Base64 Related global methods .

• btoa()： String or binary value to Base64 code .
• atob()： hold Base64 The encoding is changed to the original character .

Base64 Methods cannot operate on non ASCII character .

Example

To make a non ASCII Code character to Base64 code , You must use the method described in the previous section to Unicode Double byte string is converted to ASCII Character representation , Then use these two methods .

encodeURIComponent and decodeURIComponent Non essential . Only in URI Only when transferring parameters .

That is to say ：btoa and atob You can directly receive a string parameter .

function b64Encode (str) {
    
    return btoa(encodeURIComponent(str));
}
function b64Decode (str) {
    
    return decodeURIComponent(atob(str));
}
var b = b64Encode('JavaScript  From entry to mastery ');
var a = b64Decode(b);
console.log(b);  // return SmF2YVNjcmlwdCVFNCVCQiU4RSVFNSU4NSVBNFOSU5NyVBOCVFNSU4OCVCMCVFNyVCMiVCRSVFOSU4MCU5QQ==
console.log(a);  // return “JavaScript  From entry to mastery ”