Closes a popup.
Note: The terms popup and lightbox refer to the same element. While the editor and dashboard now refer to it as a popup, the API methods continue to use the term lightbox for backward compatibility. The documentation uses both terms accordingly.
The close() method closes a popup and allows you to pass data from the popup to the page that opened the popup.
If a popup is closed through the 'X' icon, close button, or popup overlay, data will not be returned to the original page.
To ensure data can be passed:
onClick event that calls close().The data to pass back to the openLightbox() method.