Tryit Editor v1.8

Source Code:

<!DOCTYPE html> 
<html> 
<body> 

<p>Can my browser play MP4 videos? <span>
<button onclick="supportType(event,'video/mp4','avc1.42E01E, mp4a.40.2')" type="button">Test</button>
</span></p>

<p>Can my browser play OGG videos? <span>
<button onclick="supportType(event,'video/ogg','theora, vorbis')" type="button">Test</button>
</span></p>

<script> 
function supportType(e,vidType,codType)
  { 
  myVid=document.createElement('video');
  isSupp=myVid.canPlayType(vidType+';codecs="'+codType+'"');
  if (isSupp=="")
    {
    isSupp="No";
    }
  e.target.parentNode.innerHTML="Answer: " + isSupp;
  } 
</script> 
</body> 
</html>

Result:

W3Schools.com - Try it yourself

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