HTMLButtonElement: reportValidity() method

reportValidity()

<form action="#" id="form" method="post">
  <p>
    <input type="submit" value="Submit" />
    <button id="example" type="submit" value="fixed">THIS BUTTON</button>
  </p>
  <p>
    <button type="button" id="report">reportValidity()</button>
  </p>
</form>

<p id="log"></p>

input[type="submit"],
button {
  background-color: #3333aa;
  border: none;
  font-size: 1.3rem;
  padding: 5px 10px;
  color: white;
}
button:invalid {
  background-color: #aa3333;
}
button:valid {
  background-color: #33aa33;
}

const reportButton = document.querySelector("#report");
const exampleButton = document.querySelector("#example");
const output = document.querySelector("#log");

reportButton.addEventListener("click", () => {
  const reportVal = exampleButton.reportValidity();
  output.innerHTML = `reportValidity returned: ${reportVal} <br/> custom error: ${exampleButton.validationMessage}`;
});

exampleButton.addEventListener("invalid", () => {
  console.log("Invalid event fired on exampleButton");
});

exampleButton.addEventListener("click", (e) => {
  e.preventDefault();
  if (exampleButton.value === "error") {
    breakOrFixButton("fixed");
  } else {
    breakOrFixButton("error");
  }
  output.innerHTML = `validation message: ${exampleButton.validationMessage} <br/> custom error: ${exampleButton.validationMessage}`;
});

function breakOrFixButton() {
  const state = toggleButton();
  if (state === "error") {
    exampleButton.setCustomValidity("This is a custom error message");
  } else {
    exampleButton.setCustomValidity("");
  }
}

function toggleButton() {
  if (exampleButton.value === "error") {
    exampleButton.value = "fixed";
    exampleButton.innerHTML = "No error";
  } else {
    exampleButton.value = "error";
    exampleButton.innerHTML = "Custom error";
  }
  return exampleButton.value;
}