var productMenuList = document.querySelector('.product-menu__list');
productMenuList.onmouseover = evt => {
var childrenUl = evt.target.querySelector('ul')
console.log(childrenUl)
console.log(evt.target)
if (childrenUl) {
$el = [...childrenUl.children].pop().classList.contains('show');
if (childrenUl.children.length > 3 && !$el) {
var newButtonDown = document.createElement('li');
newButtonDown.innerHTML = '<a href="#" class=\"dropdown-menu__item-link\"> Показать еще </a>';
newButtonDown.className = "dropdown-menu__item show dropdown-menu__item--grey without-dropdown";
childrenUl.append(newButtonDown);
console.log(newButtonDown)
}
}
};
console.log(evt.target)
console.log(childrenUl)
<div class="ears"></div>
.content {
margin: 0 auto;
}
<div class="messenger">
<ul>
<li><a href="#">Telegram</a></li>
<li><a href="#">WhatsApp</a></li>
<li><a href="#">Viber</a></li>
</ul>
</div>
<div class="aftermenu">
<div>
<div><a href="#">+7 (812) 989-01-51</a></div>
<div><p>Ежедневно с 10:00 - 18:00</p></div>
</div>
<div>