I'm a javascript newbie trying to hack on a rails website that somebody else created. What I want to do is open the javascript console and access variables that have been defined/created in the window.onload function. They must be hanging around in some fashion because I can interact with them via mouse clicks? To make this concrete, I want to be able to go this site http://project-pavement.herokuapp.com/map/nyc in a web browser, pop open the javascript console, and do things like add a marker to the underlying Leaflet map a la http://leafletjs.com/examples/quick-start.html.
