code: func parse(r io.Reader) *htmlDocument {
  	htmlDoc := &htmlDocument{}
  	tokenizer := html.NewTokenizer(r)
  	for {
  		if errorToken, _, _ := parseToken(tokenizer, htmlDoc, nil); errorToken {
  			break
  		}
  	}
  	return htmlDoc
  }
docs: // parse parses a stirng and converts it into an html.