Customising a popup

Hello. I'm adding a simple popup message to my page using 'behaviours' and have set the event to trigger on page load.
All is working as expected, but I wonder whether it's possible to edit/customise this behaviour? For example, the 'OK' button currently closes the window; can it be configured to link to another page on my website? Also, is it possible to change the 'IP' text (top left)?
Thanks for any advice.
