The USBConnectionEvent interface of the WebUSB API is the event type passed to USB.onconnect and USB.ondisconnect when the user agent detects that a new USB device has been connected or disconnected.

USBConnectionEvent() Experimental

Returns a USBConnectionEvent object.

USBConnectionEvent.device Read only Experimental

Returns a USBDevice object representing the current device.

In the following example listening for connect and disconnect events is used to add and remove the devices from the user interface of an application.

navigator.usb.addEventListener("connect", (event) => {
  // Add event.device to the UI.
});

navigator.usb.addEventListener("disconnect", (event) => {
  // Remove event.device from the UI.
});