SerialPort: connect event

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Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

Note: This feature is available in Dedicated Web Workers.

The connect event of the SerialPort interface is fired when a port has connected to the device. This event is only fired for ports associated with removable devices such as those connected via USB.

This event bubbles to the instance of Serial that returned this interface.


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

addEventListener("connect", (event) => {});

onconnect = (event) => {};

Event type

A generic Event.


This event bubbles to Serial. The property refers to the SerialPort object that bubbles up.

For more information, see Event bubbling.


Notify when a specific port connects

The Serial.requestPort() method returns a Promise that resolves with a SerialPort chosen by the user.

// Prompt user to choose a serial port
const port = await navigator.serial.requestPort();

port.addEventListener("connect", (event) => {
  // notify that the chosen port is connected

Listening for any newly-connected ports

The connect event bubbles up to the Serial object where you can listen for any newly-connected ports.

navigator.serial.addEventListener("connect", (event) => {
  // notify that a new port is available
  // use `` to refer to the newly-added port


Web Serial API
# dfn-connect
Web Serial API
# dom-serialport-onconnect

Browser compatibility

BCD tables only load in the browser

See also