A common question developers and business owners ask is how to enable progressive web application features on iOS and older browsers like Internet Explorer. While all features cannot be hacked in these browsers, much of it can.
When the iPhone was released, the initial application model was the web. They created an advanced experience for web apps that included the add to homescreen experience. Unfortunately, they did not make an automatic prompt experience. Who knows how advanced this might be today if developers did not cry out for the native app model.
What we can do is still leverage this capability and use Matteo Spinelli's add to homescreen library (http://cubiq.org/add-to-home-screen) in combination with Apple's guidelines. Doing so allows your web apps to launch from user's home screens...