HTML Dialog

Usage notes

• HTML <form> elements can be used to close a dialog box if they have the attribute method="dialog" or if the button used to submit the form has formmethod="dialog" set. When a <form> within a <dialog> is submitted via the dialog method, the dialog box closes, the states of the form controls are saved but not submitted, and the returnValue property gets set to the value of the button that was activated.

Accessibility

When implementing a dialog, it is important to consider the most appropriate place to set user focus. When using HTMLDialogElement.showModal() to open a <dialog>, focus is set on the first nested focusable element. Explicitly indicating the initial focus placement by using the autofocus attribute will help ensure initial focus is set on the element deemed the best initial focus placement for any particular dialog. When in doubt, as it may not always be known where initial focus could be set within a dialog, particularly for instances where a dialog's content is dynamically rendered when invoked, the <dialog> element itself may provide the best initial focus placement.

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

This dialog is initially open because of the presence of the open attribute. Dialogs that are displayed using the open attribute are non-modal. After clicking "OK", the dialog gets dismissed, leaving the Result frame empty. When the dialog is dismissed, there is no method provided to reopen it. For this reason, the preferred method to display non-modal dialogs is by using the HTMLDialogElement.show() method. It is possible to toggle the display of the dialog by adding or removing the boolean open attribute, but it is not the recommended practice.