title: Detect an application is installed or not?
body: <p>I have a application that registers a handler for custom URI on the Phone. I am able to launch the application by making a link to "myapp://act/launch" from my phone web pages. This works only if my application is installed on the device. 
  What I want to do is detect if the URI Scheme is supported from the browser and then prompt my own message saying "please download the app etc..." if the handler for the URI scheme is not found.</p>
  
  <p>Is there a way I can detect or find the list of URL Scheme handlers on the Phone from the Web Browser ?</p>