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HTML DOM Track default Property
The HTML DOM Track default property sets/returns a boolean value corresponding to whether the track is to enabled until the user’s preference contradicts it.
NOTE: Only one track should be default per media (audio/video) element.
Following is the syntax −
Returning boolean value - true/false
trackObject.default
Setting default to booleanValue
trackObject.default = booleanValue
Here, “booleanValue” can be the following −
| booleanValue |
Details |
|---|---|
| true |
It defines that track willbe default enabled |
| false |
It defines that track willnot be enabled unless user prefers to |
Let us see an example of Track default property −
Example
<!DOCTYPE html>
<html>
<head>
<title>Track default</title>
<style>
form {
width:70%;
margin: 0 auto;
text-align: center;
}
* {
padding: 2px;
margin:5px;
}
input[type="button"] {
border-radius: 10px;
}
</style>
</head>
<body>
<form>
<fieldset>
<legend>Track-default</legend>
<video id="videoSelect" controls width="250" src="sample.mp4">
<track default kind="subtitles" srclang="es" src="sample-es.srt"/>
<track kind="subtitles" srclang="en" src="sample-en.srt"/>
</video><br>
<input type="button" onclick="getTrackDetails()" value="What is the default track?">
<div id="divDisplay"></div>
</fieldset>
</form>
<script>
var divDisplay = document.getElementById("divDisplay");
var trackSelect = document.getElementsByTagName("track");
function getTrackDetails() {
for(var i=0; i<trackSelect.length; i++)
if(trackSelect[i].default)
divDisplay.textContent = 'Default track for video: '+trackSelect[i].srclang;
}
</script>
</body>
</html>
Output
Before clicking ‘What is the default track?’ button −

After clicking ‘What is the default track?’ button −

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