I have set my Cocoa app to be an URL handler for com_example_myapp: protocol (using this great tutorial). So, the link in Safari <a href="com_example_myapp://link"> now opens my app. Cool.
But before I give the user the link in the web browser, how can I determine whether the client's OS is capable to handle it? How to check this via JS (PHP, ...)?
I have found a lot of solutions (mostly for Mobile Safari) but cannot find anything cross-browser compatible.