HTML - default Attribute

The HTML default attribute is a boolean attribute that is used to indicate that a track should be enabled unless the user's preferences indicate that another track is more appropriate. It can only be used on one 'track' element per media element.

You can use the default attribute with JavaScript to check whether this attribute present in the media element or not. If present returns true, otherwise; false.

Syntax

Following is the syntax for HTML default attribute − 

<track default>

Example

In the following example, we are going to use the default attribute with the track element.

<!DOCTYPE html>
<html lang="en">
<head>
   <title>HTML 'default' attribute</title>
   <style>
      video {
         border: 5px solid black;
         border-radius: 10px;
      }
   </style>
</head>
<body>
   <!--HTML 'default' attribute-->
   <h3>Example of the HTML 'defualt' attribute</h3>
   <video width="300" controls>
      <source src="https://samplelib.com/lib/preview/mp4/sample-20s.mp4">
      <track srclang="subtitles" default>
   </video>
   <p>The user will not be able to see the video captions if the 'default' attribute is present.</p>
</body>
</html>

On running the above code, the output window will pop up displaying the video file on the webpage.

Example

Considering the another scenario, where we are going to use the default attribute with the track element of the audio.

<!DOCTYPE html>
<html lang="en">
<head>
   <title>HTML 'default' attribute</title>
   <style>
      audio {
         border: 5px solid black;
         border-radius: 10px;
      }
   </style>
</head>
<body>
   <!--HTML 'default' attribute-->
   <h3>Example of the HTML 'defualt' attribute</h3>
   <audio controls>
      <source src="https://samplelib.com/lib/preview/mp3/sample-6s.mp3">
      <track srclang="subtitles" default>
   </audio>
   <p>The user will not be able to see the video captions if the 'default' attribute is present.</p>
</body>
</html>

When we run the above code, it will generate an output consisting of the of the audio file displayed on the webpage.

html_attributes_reference.htm
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