I've tested this on few projects and it looks ok so far. Please let me know if you have any problems.
Download the zip file from
and extract it to
C:\Program Files\Construct 2\exporters\html5\plugins
After unzipping the files, you should see four files at
C:\Program Files\Construct 2\exporters\html5\plugins\cocoonjsbackbutton
Open your Scirra-project and select "Object types" from your project, right click your mouse and select "Insert new object".
From "Platform Specific", select "CocoonJSBackButton".
On your event sheet, add new event and select "CocoonJSBackButton". There is only one event available - "On back", which is triggered when user clicks Android phone back button.
Please note this disables CocoonJS normal back button behavior, so yo need to implement your own app exit function e.g. "Browser" object's "Close" method.