Just to make it clear: we're not going to add scripting in the forseeable future. The whole reason Construct 2 exists is to save you from programming. So adding it goes against our whole reason we made Construct 2 in the first place!
If you like programming, you can code HTML5 games in javascript entirely with free tools like Google Chrome (which has an excellent debugger) and Notepad++. It's a lot harder than doing it in Construct 2 though.
Kyatric's suggestion of using the SDK is also a good idea - you can use custom code and APIs there, and have it all integrate smoothly with events.