onChange event with javascript modifications of checkbox [duplicate]

I tried to check a checkbox with js and detect the change, but the event onchange not detect the change, while that is visually changing. (sorry for by bad english, i'm french) Here is an example:

document.querySelector("#checkbox").onchange = (e) => {
  let checked = e.target.checked;
  if (checked) {
    console.log("checked !");
  } else {
    console.log("unchecked...");
  }
}

document.querySelector("#buttonOn").onclick = (e) => {
  document.querySelector("#checkbox").checked = true;
}
document.querySelector("#buttonOff").onclick = (e) => {
  document.querySelector("#checkbox").checked = false;
}

<button id="buttonOn">On</button>
<button id="buttonOff">Off</button>
<input type="checkbox" name="" id="checkbox">