See, that's the problem, you wouldn't know what your converting without special tags
They can post html code and have it appear as a webpage, that can happen
But a pure text file as a webpage, without the html code, nothing can happen
Just can also have them just upload html page as a file and check for .htm/.html file extension and then store the path in the db and pull it out
Otherwise, i can't see how. Unless I am not grasping the concept, but at 5 am, this is quite possible 😉