Detect/verify URI Scheme exists before opening URL - repost

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. Note that once the press reader application is installed, it will register the URI scheme with the OS/Browswer and start the application on its own, your script does not have to actually start the press reader application. Its primary purpose is to make sure the application is installed. script must work on android and ios devices. App for testing are in app store: [login to view URL] [login to view URL]