Q:

Show 'Available in AppStore too' at upper end of page

From time to time, I do see on iOS devices web pages which have a region at the upper end of the page, which links to an app store. The text in the region reads like 'Available in AppStore too.'. 
Since all those regions share a common layout, I wonder if that's a software library or a service? Or does it is a feature of mobile Safari?
Do we have libraries to promote the related app of a web-site if a user with a correct mobile device views the site?
Update 2014-06-29
While Apple's Smart App Banners are great, only Safari 6+ will show them. 
For other iOS browsers and Android device this jQuery mobile plugin might be of help: jquery.smartbanner at GitHub.

A:

These are called 'Smart App Banners'.  All the needed details are available on the iOS Developer Library: Promoting Apps with Smart App Banners.

