Creating Well-Behaved Sites With The #page_visibility #api - Smashing Magazine
▻http://www.smashingmagazine.com/2015/01/20/creating-sites-with-the-page-visibility-api
Support for the Page Visibility API is excellent: all modern browsers, with the exception of Opera Mini, fully support the API, including IE10+. Vendor prefixes are also refreshingly absent from implementation of the spec: the only browsers that currently need a -webkit prefix are Android and Blackberry.