why you need to use js? it can be solved via css. here is fiddle with working example
<div class="lol">
<div>lol</div>
</div>
<div class="lol">
<div>lol</div>
</div>
<div class="lol">
<div>lol</div>
</div>
.lol{width:100px;height:100px; background:red;margin:10px}
.lol div{display:none}
.lol:hover div{display:block}