JSFiddle - React, Tailwind, and code Playground

HTML

<dl>
    <dt id="orig">Original string</dt>
    <dd></dd>
    
    <dt id="nums">Numbers</dt>

    <dt id="nums-segmented">Segmented Numbers</dt>
    
    <dt id="string">Reversed string</dt>
</dl>

JavaScript

var str = "κόσμε 这是一条狗 é €";

$('#orig').after('<dd>' + str + '</dd>');

var result = "";
for (var i = 0, len = str.length, code, paddedCode; i < len; ++i) {
  code = str[i].charCodeAt(0).toString();
  paddedCode = code.length >= 8
    ? code
    : new Array(8 - code.length + 1).join(0) + code; result += paddedCode;
  result += paddedCode;
}

$('#nums').after('<dd>' + result + '</dd>');

var segments = result.match(/.{8}/g);

$.each(segments, function(k, v) {
    $('#nums-segmented').after('<dd>' + v + '</dd>');
});

revertedString = '';

for (var i = 0, len = segments.length; i < len; i=i+2) {
  revertedString += String.fromCharCode((segments[i] | 0));
}

$('#string').after('<dd>' + revertedString + '</dd>');