In order for any of this to actually be SEEN by the end user, display properties must be associated with the parse tree. This requires a stylesheet parser (CSS at the very least, XSL would be nice). See the W3C Style Area for more information on stylesheets.
This component would really just be a parser and an API to get all the style information associated with a NODE from the DOM. This will be used by the display engine to actually draw text on the screen.