Window: offline event

Baseline

Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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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.

Syntax

Use the event name in addEventListener():

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

Alternatively, assign to the event handler property of the interface:

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:

Examples

// addEventListener version
window.addEventListener("offline", (event) => {
  console.log("The network connection has been lost.");
});

// onoffline version (but note that this replaces other event listeners
// added using onoffline, if any)
window.onoffline = (event) => {
  console.log("The network connection has been lost.");
};