Collapse

- collapse tag
  - expanded attribute
- On Panels:
  - collapse attribute
  - expanded attribute
- on other tags:
  - collapse-target attribute 
  - collapse-expanded attribute
- accordion tag
  - active-index atttribute
  - context attribute
- pane tag (inherits from panel)
  - id attribute (autogenerated if not set)
  - active attribute

http://getbootstrap.com/javascript/#collapse
