KeyCode script to recognize digit 11 and send an alert to the user

Question

I'm trying to make a chrome extension to know order typing error, when the user misspells 11 instead of 1 sending an alert, but the script is running in a loop

document.querySelector('body').addEventListener('keydown', function() {
  var tecla = event.keyCode;
  if (tecla == 49) {

    alert('Primeiro IF');
    document.querySelector('body').addEventListener('keydown', function(event) {
      var confirma = event.keyCode;

      if (confirma == 49) {
        alert('segundo IF');
        return false;
      }
    });


  } else if (tecla == 9) {
    alert('Tecla 9');
    return false;
  }
});

Answer 1

You added a new event listener each time you typed

Try this:

let tecla, confirma;
document.querySelector('body').addEventListener('keydown', function() {
  tecla = event.keyCode;
  if (tecla == 49) {
    if (confirma == 49) {
      console.log('Segundo 1');
      return false;
    } else {
      console.log('Primeiro 1');
      confirma = tecla
    }
  } else if (tecla == 9) {
    console.log('Tecla 9');
    tecla = "";
    confirma = "";
    return false;
  }
});