<!DOCTYPE html>
<body style="background: blue">
  <div style="position: fixed; left: 0; top: 0; width: 100%; height: 100px; background: yellow"></div>
  <div style="position: fixed; left: 0; bottom: 0; width: 100%; height: 100px; background: green"></div>
  <div style="height: 2000px"></div>
</body>
