USBDevice: opened property
The opened
read only property of the USBDevice
interface indicates whether a session has been started with a paired USB device. A device must be opened before it can be controlled by a web page.
Value
Examples
This example is for a hypothetical USB device with a multi-colored LED. It shows how to test that a device is open before calling USBDevice.controlTransferOut
to set a specified LED color.
Note: What data can be passed to a USB device and how it is passed is particular and unique to each device.
async function setDeviceColor(usbDevice, r, g, b) {
if (device.opened) {
const payload = new Uint8Array([r, g, b]);
await usbDevice.controlTransferOut(
{
requestType: "vendor",
recipient: "device",
request: 1,
value: 0,
index: 0,
},
payload,
);
}
}
Specifications
Browser compatibility
|
Desktop |
Mobile |
|
Chrome |
Edge |
Firefox |
Internet Explorer |
Opera |
Safari |
WebView Android |
Chrome Android |
Firefox for Android |
Opera Android |
Safari on IOS |
Samsung Internet |
opened |
61 |
79 |
No |
No |
48 |
No |
No |
61 |
No |
45 |
No |
8.0 |