Warning if required inputs are not selected

Question

How can I add a warning to #printpage when its disabled if its chosen saying please check required fields?

Answer 1

You can use JS function checkValidity(), this will return false if the form is not valid.

https://developer.mozilla.org/en-US/docs/Web/API/HTMLSelectElement/checkValidity

isValid = $('.form').checkValidity()

if (!isValid) {
  $('#printpage').innerText = "Please fill in required fields";
  } else {
  $('#printpage').innerText = "";
}

Your html should contain HTML validity checkers, such as required.