[css-position] events for position sticky

Hi everyone.

The specifications of position: sticky don't mention any event fired when
an element is stuck and when it returns to its original position, for
example something like stickystart and stickyend. I think this could be
very useful and it has different use cases.

The first use case is a website that needs to decrease the margin of a
navigation bar when it starts sticking. Another use case might be to have
an element that takes the full width of the page when it's sticking but a
different width when it's in its original position.

Has anyone thought about this possibility? Has this topic been discussed
before?

Thank you

-- 
Aurelio De Rosa
email:  a.derosa@audero.it
website: www.audero.it
skype: AurelioDeRosa