Dialogs #a11y #html

dialogs.html

<!-- https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dialog -->

<dialog open>
  <p>Greetings, one and all!</p>
  <!-- method="dialog" closes dialog on form submit -->
  <form method="dialog">
    <button>OK</button>
  </form>
</dialog>

<!-- Simple modal dialog containing a form -->
<dialog id="favDialog">
  <form method="dialog">
    <p>
      <label
        >Favorite animal:
        <select>
          <option value="default">Choose…</option>
          <option>Brine shrimp</option>
          <option>Red panda</option>
          <option>Spider monkey</option>
        </select>
      </label>
    </p>
    <div>
      <button value="cancel">Cancel</button>
      <button id="confirmBtn" value="default">Confirm</button>
    </div>
  </form>
</dialog>
<p>
  <button id="updateDetails">Update details</button>
</p>
<output></output>
<script>
  const updateButton = document.getElementById("updateDetails");
  const favDialog = document.getElementById("favDialog");
  const outputBox = document.querySelector("output");
  const selectEl = favDialog.querySelector("select");
  const confirmBtn = favDialog.querySelector("#confirmBtn");

  // If a browser doesn't support the dialog, then hide the
  // dialog contents by default.
  if (typeof favDialog.showModal !== "function") {
    favDialog.hidden = true;
    /* a fallback script to allow this dialog/form to function
     for legacy browsers that do not support <dialog>
     could be provided here.
  */
  }
  // "Update details" button opens the <dialog> modally
  updateButton.addEventListener("click", () => {
    if (typeof favDialog.showModal === "function") {
      favDialog.showModal();
    } else {
      outputBox.value =
        "Sorry, the <dialog> API is not supported by this browser.";
    }
  });
  // "Favorite animal" input sets the value of the submit button
  selectEl.addEventListener("change", (e) => {
    confirmBtn.value = selectEl.value;
  });
  // "Confirm" button of form triggers "close" on dialog because of [method="dialog"]
  favDialog.addEventListener("close", () => {
    outputBox.value = `${
      favDialog.returnValue
    } button clicked - ${new Date().toString()}`;
  });
</script>