Question: Adding a `mailto:` link on my site, but it occurred to me that it's possible the user may not have a client set up to handle it

I found [this](https://stackoverflow.com/questions/7591474/has-anyone-ever-come-up-with-a-way-to-detect-the-email-program-a-recipient-is-us) thread from 3 years ago and was hoping there's something doable now. I don't necessarily need to figure out what's handling their mailto links, but rather if it got handled at all. Is this possible?

Answer: 
No. =(

The answer in your link still stands today. The knowledge that something was even capable of handling the event is way to much information to give to a browser.
No, `mailto:` is very limited, the information is beyond the scope of the browser