Is there a website or tool where I can enter jQuery code and it will show me if unsupported / deprecated functions are used in this code?
That would be very nice ...
jQuery now provides a migration plugin (1.4.1 and 3.0+) to display warnings about any use of deprecated features in the browser console:
https://github.com/jquery/jquery-migrate/#readme
jQuery lint should do the following job:
http://james.padolsey.com/javascript/jquery-lint/