//4. Валидация всех форм
const editButton = document.forms.editform.elements.savebutton;
const editForm = document.forms.editform;
const editingName = document.forms.editform.elements.username;
const editingFormInfo = document.forms.editform.elements.userinfo;
function activationOfEditingButton () {
   if (editingName.value.length === 0 || editingFormInfo.value.length === 0 ) {
    editButton.setAttribute('disabled', true);
    editButton.classList.remove('button_active');
  } else {
    editButton.removeAttribute('disabled');
    editButton.classList.add('button_active');
  }
}
editForm.addEventListener("input", activationOfButton);
//с использованием параметров
function activationOfEditingButton (firstinput, secondinput, submit) {
   if (firstinput.value.length === 0 || secondinput.value.length === 0 ) {
    submit.setAttribute('disabled', true);
    submit.classList.remove('button_active');
  } else {
    submit.removeAttribute('disabled');
    submit.classList.add('button_active');
  }
}
editForm.addEventListener("input", activationOfButton(editingName, editingFormInfo, editButton));
Coll