JSFiddle - React, Tailwind, and code Playground

HTML

<a class="clickmelink">нажми на меня</a>

<tbody>
    <tr>
        <td><a class="main-menu-item" data-url="/" href="http://karkas.nanosfera.ru/">Главная</a></td>
        <td class="test-class">
            <a class="main-menu-item" data-url="/gallery" href="/gallery">Галерея ДОК</a>
            <div class="main-submenu">
                <div class="layout">
                    <ul class="main-submenu-list clear" style="padding-top: 10px; padding-bottom: 25px;">
                        <li>
                            <ul>
                                <li><a class="main-submenu-item" href="/gallery">Галерея ДОК</a></li>
                                <li><a class="main-submenu-item" href="/catalogue/review">ДОК своими глазами</a></li>
                            </ul>
                        </li>
                    </ul>
                </div>
            </div>
        </td>
    </tr>
</tbody>

JavaScript

document.body.onload = function() 
    {
        setTimeout(function()
                   {
    var clickMeLink = document.querySelector('.clickmelink');
    var addClassMenu = document.querySelector('.test-class');
            
    clickMeLink.addEventListener ('click', function () {
    addClassMenu.classList.add('hover');
    });
        }, 1000); }