#[body]#
<a class="navbar-brand d-lg-none px-2" href="?cat={cat_id}">{cat_name}</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#menuCore{root}">
    <span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse bg-secondary autosize-menu" id="menuCore{root}" style="overflow-x: clip;">
	<ul  class="navbar-nav mr-auto flex-nowrap" id="menuCoreNavbar{root}">
		{menu_item}
	</ul>
</div>

<script>
	document.addEventListener('DOMContentLoaded', function() {

		if (window.innerWidth < 768 ) return; // Только для широких экранов

		var navList = document.getElementById('menuCoreNavbar{root}');
		var navItems = navList.getElementsByClassName('nav-item');
		var moreMenu = document.createElement('li');
		moreMenu.className = 'dropdown dropdown py-0';
		moreMenu.innerHTML = '<a class="nav-link text-nowrap text-right bg-secondary align-self-baseline px-2 text-primary dropdown-toggle" href="#" data-toggle="dropdown"><i class="far fa-bars"></i> Ещё</a>' +
				'<div class="dropdown-menu dropdown-menu-right py-0" style="z-index: 999"></div>';

		var dropdownMenu = moreMenu.getElementsByClassName('dropdown-menu')[0];

		var fullWidth = 100; // Ширина кнопки Ещё
		var hideNext = false;
		for (var i = 0; i < navItems.length; i++) {
			fullWidth += navItems[i].offsetWidth
			if (fullWidth > window.innerWidth) {
				hideNext = true;
			}
			if (hideNext) {
				var clone = navItems[i].cloneNode(true);
				dropdownMenu.appendChild(clone);
				navItems[i].classList.add('d-none');
			}

		}
		if (hideNext) {
			navList.appendChild(moreMenu);
		}
	});
</script>
#[!body]#
#[item]#
<li class="nav-item"><a class="nav-link text-truncate bg-secondary align-middle px-2 text-primary" href="?cat={cat_id}"><img src="{img}" style="height: 13px; width: 13px;top: -3px; position: relative;"> {cat_name} <span class="badge badge-primary"></span></a></li>
#[!item]#
#[item_sel]#
<li class="nav-item active"><a class="nav-link text-truncate bg-grey px-2 text-primary" href="?cat={cat_id}"><img src="{img}" style="height: 13px;  width: 13px;top: -3px; position: relative;"> {cat_name} <span class="badge badge-primary"></span></a></li>
#[!item_sel]#
#[sep]##[!sep]#