JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="results"></ul>

JavaScript

function isUrl(url)
{
    if (/^((http|https):\/\/)?[a-zа-я0-9]+([\-\.]{1}[a-zа-я0-9]+)*\.[a-zа-я]{2,5}(:[0-9]{1,5})?(\/.*)?$/i.test(url)) {
        return true;
    }
    return false;
}

function recordWhetherIsUrl(url)
{
    var li = document.createElement('li');
    var u = document.createElement('u');
    var tt = document.createElement('tt');
    tt.appendChild(document.createTextNode(url));
    u.appendChild(tt);
    li.appendChild(u);
    if(isUrl(url))
        li.appendChild(document.createTextNode(" is a URL."));
    else
        li.appendChild(document.createTextNode(" is not a URL."));
    document.getElementById('results').appendChild(li);
}

recordWhetherIsUrl('http://stackoverflow.com'); // is a URL (Latin)
recordWhetherIsUrl('http://правительство.рф/'); // is a URL (Cyrillic)
recordWhetherIsUrl('http://αβγδεζηθικλμν.ξο/'); // is not a URL (Greek)