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问题:

Good day! I wonder why I cannot decode base64 response in javascript using atob or btoa or custom formulas like $.base64.decode().

This is what I have in php

$res = "Это тескт";
echo base64_decode($res);

This is what I have in jquery

$.ajax({
type: "GET",
url: "request.php",
success: function(data){
$('#elementid').html($.base64.decode(data));
//or $('#elementid').html(atob(data)); // it gives the same result as the above one.

On the page I see the following

ÐÑÐ¾ ÑÐµÑÐºÑ

Base64 encoded data looks the following way

0K3RgtC+INGC0LXRgdC60YI=

If I try to decode using different web tools from BASE64 to UTF-8 I see correct result, but not on my page using the above functions. Please suggest.

UPDATE: @logic-unit thanks for the suggestion. I forgot to mention that the resulting page index.php has the following in the heading

<?php
header('Content-Type: text/html; charset=utf-8');
?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
...
</head>

回答1:

I found an answer to the question. It seems that atob and btoa badly handle UTF-8 encoding.

It is described in https://developer.mozilla.org/en-US/docs/Web/JavaScript/Base64_encoding_and_decoding Solution 2 from section The "Unicode Problem" worked well for me.

Solution #2 – rewriting atob() and btoa() using TypedArrays and UTF-8