Online statusBaseline · Widely available
The navigator.onLine property is a boolean for whether the browser is connected to some network (though not necessarily the internet). The online and offline events fire when the connection state changes.
Supported in all major browsers for at least 30 months — safe to use without fallbacks. Baseline since Jul 29, 2015. Widely available since Jan 29, 2018.
Browser support
DesktopChrome
1–1Not supported
2+Supportedsince May 21, 2009
Current: 155Edge
12+Supportedsince Jul 29, 2015
Current: 154Firefox
1–1Not supported
1.5+Supportedsince Nov 29, 2005
Current: 157Safari
1–3.1Not supported
4+Supportedsince Jun 8, 2009
Current: 27MobileChrome Android
18+Supportedsince Jun 27, 2012
Current: 155Firefox Android
4+Supportedsince Mar 29, 2011
Current: 157Safari iOS
1–3Not supported
3.2+Supportedsince Apr 3, 2010
Current: 27How to use
This feature is Baseline widely available — use it freely, no fallback needed.
Example
Full syntax and examples are on MDN: onLine.
Feature detection
JS · check before using
if ("Navigator" in globalThis && "onLine" in Navigator.prototype) {
// Navigator.onLine is available
}Sub-features
Support for each part of the feature (6). The overall table above shows when the whole feature works.
| Sub-feature | Chrome | Edge | Firefox | Safari | Chrome Android | Firefox Android | Safari iOS |
|---|---|---|---|---|---|---|---|
| Navigator.onLine | 2 | 12 | 1.5 | 4 | 18 | 4 | 3.2 |
| Window.offline_event | 3 | 12 | 9 | 4 | 18 | 9 | 3 |
| Window.online_event | 3 | 12 | 9 | 4 | 18 | 9 | 3 |
| WorkerGlobalScope.offline_event | ✕ | ✕ | 29 | 8 | ✕ | 29 | 8 |
| WorkerGlobalScope.online_event | ✕ | ✕ | 29 | 8 | ✕ | 29 | 8 |
| WorkerNavigator.onLine | 4 | 12 | 3.5 | 4 | 18 | 4 | 5 |