title: How can I check if an app is installed from a web-page on an iPhone
body: <p>I want to create a web-page, a page that will redirect an iPhone to the <a href="https://en.wikipedia.org/wiki/App_Store_%28iOS%29" rel="noreferrer">App Store</a> if the iPhone does not have the application installed, but if the iPhone has the app installed I want it to open the application.</p>
  <p>I have already implemented a custom URL in the iPhone application, so I have a URL for the application that is something like:</p>
  <pre><code>myapp://
  </code></pre>
  <p>And if this URL is invalid, I want the page to redirect to the App Store. Is this possible at all?</p>
  <p>If I don't have the application installed on the phone and write the myapp:// URL in Safari, all I get is an error message.</p>
  <p>Even if there exists an ugly hack with JavaScript, I would really like to know.</p>