HOW TO: Logging outbound links

I like to log (and count) the usage of an outbound link in a sidebar.

The usage of
<a href="outbound-site" onclick=loggingfunction>click here</a>
does not work. It is not possible to have a function at the same time as the reference.

To be a little more precise: the reference is a link to Pinterest to let a visitor pin the post to Pinterest. The loggingfunction is an IFTTT trigger.

Does anyone can make my day and has an idea how to solve such an “issue”?

Kind regards,
Hans Stavleu