<!DOCTYPE html>
<html>
<body>
<p>In this example, we use the HTML DOM to assign an "onratechange" event to a video element. The playbackRate property is used to change the playing speed of the video.</p>
<video id="myVideo" width="320" height="240" autoplay 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="setPlaySpeed()" type="button">Set video to be play in slow motion</button>
<script>
// Get the video element with id="myVideo"
var x = document.getElementById("myVideo");
// Set the current playback speed of the video to 0.3 (slow motion)
function setPlaySpeed() {
x.playbackRate = 0.3;
}
// Assign an onratechange event to the video element, and execute a function if the playing speed of the video is changed
x.onratechange = function() {myFunction()};
function myFunction() {
alert("The playing speed of the video was changed");
}
</script>
</body>
</html>