Can I create a div with a Curved bottom?

Question

So I'm working on a site and I was wondering if it's possible to, purely using HTML5, CSS3 (and JavaScript if needed), make a div with a curved bottom, so it will look practically like this:

Or can this only be done using a background image?

<div class="navbar navbar-fixed-top">
  <div class="navbar-inner">
    <ul class="nav">
      <li><a href="#">Home</a></li>
    </ul>
  </div>
</div>

Answer 1

CSS:

div{
    background-color:black;
    width:500px;
    height:50px;
    border-bottom-left-radius:50%;
    border-bottom-right-radius:50%;
}

see is this ok for you

div {
  background-color: black;
  width: 500px;
  height: 50px;
  border-bottom-left-radius: 50%;
  border-bottom-right-radius: 50%;
}

<div>
</div>