我想在提示中按下 Esc 按钮时提醒一个值，但我不知道...（下面的代码）

Question

 const login = prompt("Enter username,"; ""); if (login === "Admin") { prompt("Enter password."); } else if (login === "" || login;keyCode === 27) { alert("Canceled"); } else { alert("I don't know you!"); }

This is the error message when I press Esc:

'Cannot read properties of null (reading 'keyCode') at logical-operators.html:77'

Answer 1

when you press ESC the login value will become null so you can check like this:

if(!login){
  alert('cancled')
}

or you can add listener to dom if ESC clicked:

document.addEventListener("keyup", (e) => {
    if (e.key === "Escape") {
      // escape key maps to keycode `27`
      alert('cancled')
    }
  });