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  <h2>Using the <code>WheelEvent</code> Interface</h2>
  <p>In addition to traditional mouse events like click and scroll, you can also detect mouse wheel events and get some info from the <code>event</code> object.</p>
  <p>Try scrolling your mouse wheel up or down. The page will display info about the wheel event. You can also hold the SHIFT key while moving the mouse wheel to move horizontally (left/right) instead of vertically (up/down).</p>
  <output>[Scroll your mouse wheel]</output>


                body {
  font-family: Arial, sans-serif;
  font-size: 20px;
  padding: 0 20px;
  width: 3000px;
  height: 2000px;

main {
  max-width: 800px;

p {
  text-align: left;
  padding: 0 20px;

code {
  color: firebrick;

output {
  position: fixed;
  border: solid 1px #ccc;
  padding: 14px;


                let op = document.querySelector('output'),

document.addEventListener('wheel', function (e) {
  if (e.deltaY > 0) {
    msg = `You scrolled vertically down the page ${e.deltaY}px`;
  } else {
    msg = `You scrolled vertically up the page ${Math.abs(e.deltaY)}px`;

  op.innerHTML = msg;
}, false);