W3Schools Tryit Editor

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<h1>HTML DOM Events</h1>
<h2>The ontimeupdate</h2>

<p>Attach a "timeupdate" event to a video element.</p>
<p>When the user plays the video, or skips to a new position, a function will display the position (in seconds) of the playback:</p>

<video id="myVideo" width="320" height="240" controls>
  <source src="movie.mp4" type="video/mp4">
  <source src="movie.ogg" type="video/ogg">
  Your browser does not support the video tag.
</video><br>

<button onclick="setCurTime()" type="button">Set time position to 5 seconds</button>

// Attach a "timeupdate" event to the video
video.addEventListener("timeupdate", getCurTime);

// Display the current playback position:
function getCurTime() { 
  document.getElementById("demo").innerHTML = "The playback position is " + video.currentTime + " seconds.";
}

// Set the current playback position to 5 seconds
function setCurTime() { 
  video.currentTime = 5;
} 
</script>

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