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.

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:

• HTMLBodyElement
• HTMLFrameSetElement
• SVGSVGElement

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.");
};

Specifications

Browser compatibility

See also

• online