You can activate/deactivate JavascriptConsole by clicking Windows - Developer Tools - JavascriptConsole. This window implements basic functions of modern browser's console. There can be one or more JavascriptContexts running, so you can select JavascriptContext in dropdown list.

TIP You may pass an object which needs to be inspected run-time by exposing it as a global var.

global.XYZ = 'This is the magic string I want to inspect'

And then you can inspect the object by typing 'XYZ' in console window.