files/en-us/web/api/window/offline_event/index.md
{{APIRef}}
The offline event of the {{domxref("Window")}} interface is fired when the browser has lost access to the network and the value of {{domxref("Navigator.onLine")}} switches to false.
Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}}, or set an event handler property.
addEventListener("offline", (event) => { })
onoffline = (event) => { }
A generic {{domxref("Event")}}.
In addition to the Window interface, the event handler property onoffline is also available on the following targets:
// addEventListener version
window.addEventListener("offline", (event) => {
console.log("The network connection has been lost.");
});
// onoffline version
window.onoffline = (event) => {
console.log("The network connection has been lost.");
};
{{Specifications}}
{{Compat}}