HTML5
 
 
  4.11.2 The summary element
  
   - Categories:
 
   - None.
 
   - Contexts in which this element can be used:
 
   - As the first child of a 
details element. 
   - Content model:
 
   - Phrasing content.
 
   - Content attributes:
 
   - Global attributes
 
   - DOM interface:
 
   - Uses 
HTMLElement. 
  
  The summary element represents a
  summary, caption, or legend for the rest of the contents of the
  summary element's parent details
  element, if any.