title_body: How to simulate an epub ereader and inspect its DOM?
upvoted_answer: For editing an EPub, I would look into sigil. It has the ability of WYSIWYG editing and comes recommended by other users on this forum. It's free and open-source.
  
  An alternative is Calibre. Editing EPubs is a bit more code-centric in contrast to sigil. It's also free and open-source.
  
  For some comparisons between the two programs, check out this blog.
  
  As far as an actual hardware emulator for specific eReader devices, I'm not aware of any.