Detect User Scroll Behavior: Clicking Scrollbar or Content

When it comes to detecting user scroll behavior, there are a few different approaches you can take depending on your specific needs. One common need is to differentiate between when a user clicks on the scrollbar versus when they are scrolling by using the content itself.

Method 1: Event Listeners

One way to detect this behavior is by attaching event listeners to the scrollbar and the content itself. You can use the scroll event to detect when the user is scrolling, and then use the mousedown event to detect when they are clicking on the scrollbar.

<div id="content">
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam euismod, velit vel pellentesque vestibulum, nisl enim gravida eros, vel consectetur enim ex nec justo. Donec id velit nec justo tincidunt malesuada. Nam sit amet lacinia lectus. </p>
  <p>In hac habitasse platea dictumst. Sed cursus dolor in tellus auctor, nec finibus ligula ornare. Donec quis urna libero. Nam ut lorem nec augue scelerisque consequat vel at eros. </p>
  <p>Mauris eget dolor aliquet, venenatis felis vel, vestibulum sapien. Integer ac dolor et risus accumsan varius eget sit amet augue. </p>
</div>

<script>
  const content = document.getElementById("content");

  content.addEventListener("scroll", () => {
    console.log("User is scrolling through content.");
  });

  content.addEventListener("mousedown", (event) => {
    if (event.target.id === "scrollbar") {
      console.log("User clicked on scrollbar.");
    }
  });
</script>

In this example, we listen for the scroll event and log a message when the user is scrolling through the content. We also listen for the mousedown event and check if the target of the event is the scrollbar. If it is, we log a message indicating that the user clicked on the scrollbar.

Method 2: CSS Pseudo-Classes

Another approach is to use CSS pseudo-classes to style the scrollbar and detect when the user interacts with it. This method only works in certain browsers, but it can be a simple and effective solution in those cases.

<div id="content">
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam euismod, velit vel pellentesque vestibulum, nisl enim gravida eros, vel consectetur enim ex nec justo. Donec id velit nec justo tincidunt malesuada. Nam sit amet lacinia lectus. </p>
  <p>In hac habitasse platea dictumst. Sed cursus dolor in tellus auctor, nec finibus ligula ornare. Donec quis urna libero. Nam ut lorem nec augue scelerisque consequat vel at eros. </p>
  <p>Mauris eget dolor aliquet, venenatis felis vel, vestibulum sapien. Integer ac dolor et risus accumsan varius eget sit amet augue. </p>
</div>

<style>
  #content::-webkit-scrollbar {
    width: 10px;
  }

  #content::-webkit-scrollbar-thumb {
    background-color: #888;
  }

  #content::-webkit-scrollbar-thumb:hover {
    background-color: #555;
  }
</style>

In this example, we use the ::-webkit-scrollbar pseudo-class to style the scrollbar. We can then use the :hover pseudo-class on the ::-webkit-scrollbar-thumb to detect when the user is hovering over the scrollbar. We could also use the :active pseudo-class to detect when the user clicks on the scrollbar.

Both of these methods can be effective for detecting user scroll behavior. The choice between them will depend on your specific needs and the browsers you need to support.