I believe the definition of that function is in datacapture_events.js . I've just finished struggling with the same thing, and the tool that helped me the most is (assuming you're on windows) AstroGrep. It will allow you to search for specific text within a folder (in this case, your install root). In this way, you can find references to functions/objects from other js.As an aside, I think you'd be better off building in a 'ceiling' argument as part of your URL path for your browser. This way you have full control of everything yourself. If you need any further guidance, please let me know.
My idea is first to find that function and then to modify it to take an argument (ceiling dir path) . Can you mention the path of file. I am using windows, TS 7.2.1
Can't help but point out that this is an unsupported approach that is more than likely going to break the file browser in places other than the one you're specifically targeting.If the idea is to modify the browser specifically when it's called up from TinyMCE plugins (link and image and such), then I suggest you create new TinyMCE plugins based off the existing ones, and modify those to call your own browser rather than trying to hook in anything from the internal datacap JS files at all.