Perform function after Facebook share

Perform function after Facebook share

I was wonder if there was a way to confirm that a user has shared a post
from my website, I'm trying to have an email sent out to the user after
they share my post. The emails will all be collected from my site, not
from the facebook api. I just need to know if there is any way to call
back a confirmation on the sharing system.
<a href="#"
onclick="
window.open(
'https://www.facebook.com/sharer/sharer.php?u='+encodeURIComponent(location.href),
'facebook-share-dialog',
'width=626,height=436');
return false;">
Share on Facebook
</a>