<!DOCTYPE html>
<html>
<head>
<style>
.container {
  width: 200px;
  height: 200px;
  overflow: scroll;
  position: relative;
}
</style>
</head>
<body>
<div class="container">
  <div style="background: green; height: 40px;"></div>
  <div style="height: 300px;"></div>
</div>
</body>
</html>