Which javascript events are available to open a popup from a link?

Which javascript events are available to open a popup from a link? In the PopUp admin area, it says that I can access the PopUp I created via #popup and it works fine for the css styling within the admin area editor. However, on a return jQuery $.post(){} call I would like to open the popup. How is this done? Which event? I've tried $('#popup').show(), $('#popup').open(), to no avail. What am I missing here?