[html] scrollable div inside container

I created an enhanced version, based on Trey Copland's fiddle, that I think is more like what you wanted. Added here for future reference to those who come here later. Fiddle example

    <body>
<style>
.modal {
  height: 390px;
  border: 5px solid green;
}
.heading {
  padding: 10px;
}
.content {
  height: 300px;
  overflow:auto;
  border: 5px solid red;
}
.scrollable {
  height: 1200px;
  border: 5px solid yellow;

}
.footer {
  height: 2em;
  padding: .5em;
}
</style>
      <div class="modal">
          <div class="heading">
            <h4>Heading</h4>
          </div>
          <div class="content">
              <div class="scrollable" >hello</div>
          </div>
          <div class="footer">
            Footer
          </div>
      </div>
    </body>