Detect/verify URI Scheme exists before opening URL

Problem: When a URI is entered/launched from a mobile browser that contains an “invalid” or “unknown” URI scheme an error is displayed. I need a script that will catch this type of error and display a custom message instead of a default browser error message. When the URI scheme is known, I need the application to start with no other messages. What I require from you: I need a mobile web page that contains a button that says “launch press reader”. The button will launch the URL of “PressReader://[login to view URL]”. If the press reader application is installed, the device will launch the press reader application connecting to the host www.pressreader.com. If the application is NOT installed a message will be displayed to the user “You must install the press reader application before launching”. No other error messages should be displayed.