How to Edit Facebook Event Using Javascript

[superstackerhacker]

Ok, this is my first post, but I hope that it sparks some interesting discussion.

My friend on facebook created an event (invite only.) On that event he had forgotten to put a location and an event picture. By typing in a location in the add location box I successfully changed the "location" of the event to Moscow, to the surprise of my friend. I also managed to add a picture for the event, even though I didn't have admin permissions. Once added though, location and the picture couldn't be changed by me again and only the admin could change it.
Would it be possible to change the picture, the location, and possibly the description of an event on facebook by using a javascript code that you can paste into the URL bar?

Thanks in advance.
I'm looking forward to the responses.