togglePopover method
The togglePopover() method of the HTMLElement interface toggles a
Popover_API element (i.e. one that has a valid
popover
attribute) between the hidden and showing states.
When togglePopover() is called on an element with the
popover
attribute:
- A 
HTMLElement.beforetoggle_eventevent is fired. - The popover toggles between hidden and showing:
 - If it was initially showing, it toggles to hidden.
 - If it was initially hidden, it toggles to showing.
 - A 
HTMLElement.toggle_eventevent is fired. 
Implementation
external bool togglePopover([bool force]);