key captured but not working js + shortkeys+ chrome

Added code to run js function in shortkeys extension

https://chromewebstore.google.com/detail/logpjaacgmcbpdkdchjiaagddngobkck

window.addEventListener("keydown", function(e){

  if (e.ctrlKey && e.key === 's') {
    e.preventDefault();
    alert('Save!');
  }
});

keys are being captured but nothing is happening

tried pressing the key combination (Ctrl+S) and was expecting an alert window from chrome with the message “Save!”