Shuryga, так шоль?
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title></title>
<!--<script src="http://code.jquery.com/jquery-latest.js"></script>-->
<style>
.menu ul {
display: flex;
justify-content: center;
list-style: none;
margin: 0;
font: 1em/1.2 Tahoma, sans-serif;
}
.item {
margin-right: 50px;
padding: 10px 20px;
background: orange;
}
span {
display: none;
}
.description {
min-height: 50px;
background: transparent;
font: 1em/1.2 Tahoma, sans-serif;
padding: 10px;
color: white;
}
</style>
<body>
<div class="menu">
<ul>
<li class="item">
<a href="#">Item 1</a>
<span>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Exercitationem inventore neque non praesentium quia quibusdam, sequi tenetur ullam veniam voluptatibus. Aspernatur dolor repellat voluptatum! Assumenda explicabo quasi quo temporibus voluptates?</span>
</li>
<li class="item">
<a href="#">Item 2</a>
<span>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus aperiam asperiores autem, cumque esse impedit laudantium maiores minima modi nesciunt praesentium quam quasi, quidem sit tenetur ut voluptatum. Doloribus, harum!</span>
</li>
<li class="item">
<a href="#">Item 3</a>
<span>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Architecto corporis incidunt maxime, minus molestias natus porro recusandae reiciendis reprehenderit vero. Consectetur explicabo impedit incidunt qui quibusdam repudiandae rerum voluptas voluptatum!</span>
</li>
</ul>
<div class="description"></div>
</div>
<script>
var ul = document.querySelector('.menu'),
div = document.querySelector('.description'), currentSpan;
ul.onmouseover = function(e) {
if ( e.target.tagName.toLocaleLowerCase() != 'li' || currentSpan ) return;
currentSpan = e.target.children[1];
div.style.background = 'green';
div.innerHTML = currentSpan.textContent;
};
ul.onmouseout = function(e) {
if ( e.relatedTarget == div || e.target.contains(e.relatedTarget) || !currentSpan ) return;
div.innerHTML = '';
div.style.background = '';
currentSpan = null;
};
</script>
</body>
</html>
