Window: offline event

The offline event of the Window interface is fired when the browser has lost access to the network and the value of Navigator.onLine switches to false.


Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("offline", (event) => {});
onoffline = (event) => {};

Event type

A generic Event.

Event handler aliases

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.");


HTML Standard
# event-offline
HTML Standard
# handler-window-onoffline

Browser compatibility

BCD tables only load in the browser

See also