The HTMLDialogElement interface provides methods to manipulate <dialog> elements. It inherits properties and methods from the HTMLElement interface.

Inherits properties from its parent, HTMLElement.

HTMLDialogElement.open

A boolean value reflecting the open HTML attribute, indicating whether the dialog is available for interaction.

HTMLDialogElement.returnValue

A string that sets or returns the return value for the dialog.

Inherits methods from its parent, HTMLElement.

HTMLDialogElement.close()

Closes the dialog. An optional string may be passed as an argument, updating the returnValue of the dialog.

HTMLDialogElement.show()

Displays the dialog modelessly, i.e. still allowing interaction with content outside of the dialog.

HTMLDialogElement.showModal()

Displays the dialog as a modal, over the top of any other dialogs that might be present. Everything outside the dialog are inert with interactions outside the dialog being blocked.

cancel

Fired when the user dismisses the current open dialog with the escape key.

close

Fired when the dialog is closed, whether with the escape key, the HTMLDialogElement.close() method, or via submitting a form within the dialog with method="dialog".

The following example shows a button that, when clicked, opens a modal <dialog> containing a form via the HTMLDialogElement.showModal() function. While open, everything other than the modal dialog's contents is inert. From there you can click the Cancel button to close the dialog (via the HTMLDialogElement.close() function), or submit the form via the submit button. Selecting the cancel button closes the dialog, creating a close event, not a cancel event.

HTML

<!-- pop-up dialog box, containing a form -->
<dialog id="favDialog">
  <form method="dialog">
    <p>
      <label for="favAnimal">Favorite animal:</label>
      <select id="favAnimal" name="favAnimal">
        <option></option>
        <option>Brine shrimp</option>
        <option>Red panda</option>
        <option>Spider monkey</option>
      </select>
    </p>
    <div>
      <button id="cancel" type="reset">Cancel</button>
      <button type="submit">Confirm</button>
    </div>
  </form>
</dialog>

<div>
  <button id="updateDetails">Update details</button>
</div>

JavaScript

const updateButton = document.getElementById("updateDetails");
const cancelButton = document.getElementById("cancel");
const dialog = document.getElementById("favDialog");
dialog.returnValue = "favAnimal";

function openCheck(dialog) {
  if (dialog.open) {
    console.log("Dialog open");
  } else {
    console.log("Dialog closed");
  }
}

// Update button opens a modal dialog
updateButton.addEventListener("click", () => {
  dialog.showModal();
  openCheck(dialog);
});

// Form cancel button closes the dialog box
cancelButton.addEventListener("click", () => {
  dialog.close("animalNotChosen");
  openCheck(dialog);
});

Result

• The HTML element implementing this interface: <dialog>.