title: Show alert if Chrome/Firefox extension is not installed
body: <p>I have a website with a lot of TV channels. Most of them without web player so they need a Chrome/Firefox extension like "Native HLS Playback".</p>
  
  <p>Chrome:
  <a href="https://chrome.google.com/webstore/detail/native-hls-playback/emnphkkblegpebimobpbekeedfgemhof" rel="nofollow noreferrer">https://chrome.google.com/webstore/detail/native-hls-playback/emnphkkblegpebimobpbekeedfgemhof</a></p>
  
  <p>Firefox:
  <a href="https://addons.mozilla.org/en-US/firefox/addon/native_hls_playback/?src=recommended" rel="nofollow noreferrer">https://addons.mozilla.org/en-US/firefox/addon/native_hls_playback/?src=recommended</a></p>
  
  <p>Is there any way to show a message or open the extension website automatically if detects that it's not installed?</p>
  
  <p>Thank you.</p>