title: Launch app from link, if no app then go to download app from web
body: <p>So I'm looking to launch a mobile app when a web page is landed on. I've seen this done and all is great there (see code below with Facebook and Pandora as an example). But I'm looking for a logic check to route the user one way or the other depending upon the successful or unsuccessful launch of the app. It was said in a previous solution that you cannot use a link to check the user's mobile device to see if an app is installed, but I keep thinking that there might be a way to see if the user's app was successfully launched after-the-fact and route them based on that. </p>
  
  <p>Using the code below, if the app is launched, the web page falls away, if you will (disappears into the background while the app takes center stage). If, however, the app isn't installed on the mobile device, then the web page stays up and you get an error (can't recall off-hand which error). But it seems to me that receipt of this error should be able to trigger a re-routing to a specific URL of your choice. Not at the server-level, but at the code-level. In other words... if the app launches, then grats... enjoy! But if the page loads with an error, then it redirects instantly to say, the app download page on Apple or Google (depending upon the OS detected).</p>
  
  <p>Does anyone have a suggestion as to how to make this happen? Essentially one piece of code that is looking for the trigger error and reacting to that as a way to A) launch the app from a page load (link) B) open the app store in a browser to download the app if the app wasn't successfully launched.</p>
  
  <p>This is my first foray into Stack, but I have found the community very helpful over the years. </p>
  
  <pre><code>&lt;script type="text/javascript"&gt; // &lt;![CDATA[
  var isMobile = {
      Android: function() {
          return navigator.userAgent.match(/Android/i);
      },
      BlackBerry: function() {
          return navigator.userAgent.match(/BlackBerry/i);
      },
      iOS: function() {
          return navigator.userAgent.match(/iPhone|iPad|iPod/i);
      },
      Opera: function() {
          return navigator.userAgent.match(/Opera Mini/i);
      },
      Windows: function() {
          return navigator.userAgent.match(/IEMobile/i);
      },
      any: function() {
          return (isMobile.Android() || isMobile.BlackBerry() || isMobile.iOS() || isMobile.Opera() || isMobile.Windows());
      }
  };
  
  
  
  if ( isMobile.Android() ) {
      document.location.href = "fb://profile";
  }
  else if(isMobile.iOS())
  {
      document.location.href="pandora://";
  }
  &lt;/script&gt;
  </code></pre>