<div class="link">
  <div class="button">кнопка</div>
  <div class="hidden"></div>
</div>

.button {
  width: 200px;
  background: lightgray;
  text-align: center;
}
.link {
  position: relative;
}
.hidden {
  position: absolute;
  top: 30px;
  display: none;
  width: 200px;
  height: 300px;
  background-color: pink;
}
.hidden.active {
  display: block;
}

$('.button').mouseenter( function(){
  $('.hidden').toggleClass('active');
})

$('.hidden').mouseout( function(){
  $('.hidden').toggleClass('active');
})