Undetectable and Unblocked auto-play

Auto play getting muted in both firefox and chrome. How can we code, so it won't get blocked by browsers.

My Code :

  <audio id="audio1" src="https://notificationsounds.com/storage/sounds/file-sounds-1217-relax.mp3" autoplay="">
  <script>
     a = document.getElementById('audio1');
     
     a.onended = function(){setTimeout("a.play()", 1000)}
  </script>