The code inside this element is called when the binding is removed from an element. You can use this to unload resources to free memory. The destructor should be placed inside the implementation element.
The code contained in the action value is executed for the destructor. Alternatively, you can put the code inside the destructor element.
Type: element id, must be unique in the window
A unique identifier so that you can identify the destructor with. You can use this as a parameter to getElementById and other DOM functions and to reference the element in style sheets.