WP Popups includes some API functions accessible in javascript, so if for example, you want to open a popup programmatically using Javascript you could use:
Remember! You still need to configure the display rules of the popup to make it available on the desired pages or it won’t open.
window.wppopups.showPopup(123);
In this example, we will open the popup with ID 123. If the popup cookies are already been set the popup won’t open unless you “force” it by passing “true” as the second argument of that function.
// force the popup to open window.wppopups.showPopup(123, true);
Learn how to close a popup or destroy it in the Javascript functions docs page.