HTML Video poster Property: Video Poster

HTML Video poster Property: Displaying a Placeholder Image

The HTML poster attribute for the <video> element specifies an image to be shown while the video is downloading, or until the user hits the play button. It acts as a visual placeholder and provides users with a preview or key scene from the video content.

Purpose of the poster Attribute

The primary purposes of using the poster attribute are to:

• Improve User Experience: Give users a visual indication of the video’s content before playback.
• Enhance Aesthetics: Display a visually appealing image that represents the video.
• Reduce Load Time Perception: Provide something to look at while the video is loading.

Syntax of the poster Attribute

The poster attribute is added directly to the <video> tag. The value should be a URL pointing to the image file.

<video src="your-video.mp4" poster="your-poster-image.jpg" controls></video>

Attributes

The poster attribute does not have any specific attributes besides the URL to the image file.

Examples of Using the poster Attribute

Let’s explore several examples demonstrating how to use the poster attribute effectively.

Basic Example

This example shows a basic usage of the poster attribute with a local image.

<video width="400" controls poster="images/poster-basic.jpg">
  <source src="videos/your-video.mp4" type="video/mp4" />
  Your browser does not support the video tag.
</video>

In this case, the image images/poster-basic.jpg will be displayed until the video starts playing.

Using a Remote Image

You can also use an image hosted on a remote server as the poster.

<video
  width="400"
  controls
  poster="https://www.example.com/images/remote-poster.jpg"
>
  <source src="videos/your-video.mp4" type="video/mp4" />
  Your browser does not support the video tag.
</video>

Here, the video will display the image from the specified URL.

Ensuring Proper Image Size

For the best visual experience, ensure the poster image is appropriately sized and has the same aspect ratio as the video.

<video width="640" height="360" controls poster="images/poster-sized.jpg">
  <source src="videos/your-video.mp4" type="video/mp4" />
  Your browser does not support the video tag.
</video>

Using width and height ensure your poster image is displayed correctly.

Dynamically Changing the Poster Image with JavaScript

You can also change the poster image dynamically using JavaScript.

<video id="myVideo" width="400" controls poster="images/default-poster.jpg">
  <source src="videos/your-video.mp4" type="video/mp4" />
  Your browser does not support the video tag.
</video>

<button onclick="changePoster()">Change Poster</button>

<script>
  function changePoster() {
    var videoElement_poster = document.getElementById("myVideo");
    videoElement_poster.poster = "images/new-poster.jpg";
  }
</script>

In this example, clicking the button will change the poster image to images/new-poster.jpg.

Using a Placeholder When the Video Fails to Load

You can use JavaScript to set a default poster if the video fails to load.

<video
  id="videoFallback"
  width="400"
  controls
  poster="images/default-poster.jpg"
>
  <source src="videos/nonexistent-video.mp4" type="video/mp4" />
  Your browser does not support the video tag.
</video>

<script>
  var videoElement_fallback = document.getElementById("videoFallback");
  videoElement_fallback.addEventListener("error", function () {
    videoElement_fallback.poster = "images/fallback-poster.jpg";
  });
</script>

If videos/nonexistent-video.mp4 fails to load, the poster will be updated to images/fallback-poster.jpg.

Implementing a Custom Play Button

You can overlay a custom play button on the poster image using CSS and JavaScript.

<div style="position: relative; width: 400px;">
  <video
    id="customPlay"
    width="400"
    controls
    poster="images/poster-custom-play.jpg"
    style="position: relative; z-index: 1;"
  >
    <source src="videos/your-video.mp4" type="video/mp4" />
    Your browser does not support the video tag.
  </video>
  <button
    id="playButton"
    style="
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      z-index: 2;
      background-color: rgba(0, 0, 0, 0.5);
      color: white;
      border: none;
      padding: 10px 20px;
      cursor: pointer;
    "
    onclick="playVideo()"
  >
    Play
  </button>
</div>

<script>
  function playVideo() {
    var videoElement_play = document.getElementById("customPlay");
    var playButton_play = document.getElementById("playButton");
    videoElement_play.play();
    playButton_play.style.display = "none";
  }

  document.getElementById("customPlay").addEventListener("play", function () {
    document.getElementById("playButton").style.display = "none";
  });

  document.getElementById("customPlay").addEventListener("pause", function () {
    document.getElementById("playButton").style.display = "block";
  });
</script>

This example overlays a “Play” button on the poster and hides it when the video starts playing, and shows the play button again when video is paused.

Real-World Applications of the poster Attribute

The poster attribute is beneficial in various scenarios:

• Video Streaming Platforms: Displaying a frame from the video or a custom thumbnail.
• Educational Websites: Showing a relevant image that represents the lesson or topic.
• E-commerce Sites: Featuring a product image as the video poster.
• News Portals: Using a relevant image to attract attention and provide context.

Browser Support

The poster attribute is supported by all modern browsers, ensuring consistent behavior across different platforms.

Conclusion

The HTML video poster attribute is a valuable tool for enhancing user experience by providing a visual placeholder before video playback. It supports basic implementation, remote images, dynamic changes through JavaScript, fallback mechanisms, and custom play buttons. It is supported by all modern browsers, and is widely used in streaming, education, e-commerce, and news portals. Use it to attract and inform your audience effectively.