Javascript for "Add to Home Screen" on iPhone?

There is an open source Javascript library that offers something related : mobile-bookmark-bubble

The Mobile Bookmark Bubble is a JavaScript library that adds a promo bubble to the bottom of your mobile web application, inviting users to bookmark the app to their device's home screen. The library uses HTML5 local storage to track whether the promo has been displayed already, to avoid constantly nagging users.

The current implementation of this library specifically targets Mobile Safari, the web browser used on iPhone and iPad devices.

The only way to add any book marks in MobileSafari (including ones on the home screen) is with the builtin UI, and that Apples does not provide anyway to do this from scripts within a page. In fact, I am pretty sure there is no mechanism for doing this on the desktop version of Safari either.

Until Safari implements Service Worker and follows the direction set by Chrome and Firefox, there is no way to add your app programatically to the home screen, or to have the browser prompt the user

However, there is a small library that prompts the user to do it and even points to the right spot. Works a treat.

https://github.com/cubiq/add-to-homescreen