code: func emptyElementSelector(n *html.Node) bool {
  	if n.Type != html.ElementNode {
  		return false
  	}
  
  	for c := n.FirstChild; c != nil; c = c.NextSibling {
  		switch c.Type {
  		case html.ElementNode, html.TextNode:
  			return false
  		}
  	}
  
  	return true
  }
docs: // emptyElementSelector is a Selector that matches empty elements.