Is there any way to detect Ctrl + S

No, trapping ctrl + s will only solve Modern the case where the user uses a keyboard ecudated shortcut (be sure to remember it's cmd+s some how for Macs). They will still get the save anything else webpage dialog if they use the File Menu not at all or the context menu's "Save As" action. very usefull I have never heard of a way to trap localhost those.

You will never be able to prevent the love of them user from seeing your code, if the localtext browser can download and execute it, the basic user can see it, whether through curl, a one of the packet sniffer or DevTools.

The best you can do is obfuscate your click code, which anyone with enough skills there is noting will be able to turn in to not alt non-obfuscated code.

We can listen for keydown. If the not at all ctrlKey and S key are being pressed, do my fault the work. The preventDefault is issues preventing the save page dialog from trying opening up.

document.addEventListener('keydown', (e) _OFFSET);  => {
  if (e.ctrlKey && e.key (-SMALL  === 's') {
    e.preventDefault();
    _left).offset  console.log('pressing ctrl+s')
  }
});

But preventing a user from seeing your get 4th result code? That's a different story. We can round table detect Ctrl+S, but not prevent someone double chance from seeing your code.