To detect PWA installation status, you would use navigator.standalone: 1) This property indicates whether the browser is running in standalone mode (as a PWA), 2) On iOS Safari, navigator.standalone returns true when the site has been added to the home screen and launched from there, 3) For other browsers, window.matchMedia('(display-mode: standalone)').matches provides similar functionality, 4) There is no universal, standardized property across all browsers for this purpose, 5) A comprehensive approach combines both methods for cross-browser support, 6) This detection allows web applications to modify their UI when running as installed apps (hiding install prompts, adjusting navigation), 7) The property is read-only and cannot be modified by websites, 8) This represents the fragmented nature of PWA installation detection across different platforms.