The closedBy property of the HTMLDialogElement interface indicates the types of user actions that can be used to close the associated <dialog> element. It sets or returns the dialog's closedby attribute value.
A string; possible values are:
anyThe dialog can be dismissed with a light dismiss user action, a platform-specific user action, or a developer-specified mechanism.
closerequestThe dialog can be dismissed with a platform-specific user action or a developer-specified mechanism.
noneThe dialog can only be dismissed with a developer-specified mechanism.
If the closedby attribute is absent or invalid, it falls back to the Auto state. In the Auto state:
<dialog> is opened with showModal(), it behaves as if: closedby="closerequest"<dialog> is opened by any other means, it behaves as if: closedby="none"closedBy usage<dialog closedby="any">
<p>
Closable using the <kbd>Esc</kbd> key, or by clicking outside the dialog
("light dismiss").
</p>
</dialog>const dialog = document.querySelector("dialog");
dialog.showModal();
log(`closedBy: ${dialog.closedBy}`);<dialog> element