I’m trying to add a hotkey functionality to my Google Chrome extension. If the user holds Alt, a class is added to body.

The problem is that if user changes browser tab, window, or clicks in dev tools area the class is not removed. How I can make sure the class gets removed when the current tab loses “focus”?

document.addEventListener('keydown', keydown);
var showing = false;

function keydown(evt) {
    if (evt.altKey && showing == false) {
     document.body.classList.add('key-pressed');
      }
}


document.addEventListener('keyup', keyup);

function keyup(evt) {
if (evt.key === 'Alt') {
        showing = false;
        document.body.classList.remove('op-key-pressed');
    } 
}