Firefox3.5+Safari4+Chrome2+Opera10.6+Edge79+Edge (Legacy)12+Internet Explorer10+Firefox Android?Safari iOS5+Chrome Android?WebView Android?Samsung Internet?Opera Android11+ 10.1 Introduction 10.1.1 Scope This section is non-normative. This specification defines an API for running scripts in the background independently of any user interface scripts. This allows for long-running scripts that are no