BluetoothCharacteristicProperties.writeWithoutResponse - Web APIs
the writewithoutresponse read-only property of the bluetoothcharacteristicproperties interface returns a boolean that is true if the writing to the characteristic without response is permitted.
... syntax var aboolean = bluetoothcharacteristicproperties.writewithoutresponse; value a boolean.

BluetoothCharacteristicProperties - Web APIs
writewithoutresponseread only returns a boolean that is true if the writing to the characteristic without response is permitted.
... nochrome android full support 56firefox android no support noopera android full support yessafari ios no support nosamsung internet android full support 6.0writewithoutresponse experimentalchrome full support 56notes full support 56notes notes chromeos and macos only.