Compares current properties of window object to contents of fresh window object, effectively listing global Javascript variables from the page. This works only on a browser (no NodeJS etc).
Tested on Firefox 15, Opera 12.02 and Chromium 18.
Include browserGlobals.js as the last file to the page and open inspector console (Ctrl+Shift+I in some browsers) to see the result.
Alternately, copy-paste contents of browserGlobals.js to inspector console and run it (press Enter or Ctrl+Enter).
// Surf to about:blank and open inspector console
> // Copy-paste and run the code
New globals: 0 []
// Introduce a new global:
> newGlobal = 5;
> // Copy-paste and run the code
New globals: 1 ["newGlobal"]