How to enable the camera on the click of a button?

let startScanBtn = document.getElementById("StartScanning"); // double check the ID of the button

startScanBtn.addEventListener("click", async function () {
  router = await Dynamsoft.CVR.CaptureVisionRouter.createInstance();
  let view = await Dynamsoft.DCE.CameraView.createInstance();
  cameraEnhancer = await Dynamsoft.DCE.CameraEnhancer.createInstance(view);
  router.setInput(cameraEnhancer);
  const resultReceiver = new Dynamsoft.CVR.CapturedResultReceiver();
  resultReceiver.onCapturedResultReceived = (result) => {
    /* Do something with the result */
  };
  router.addResultReceiver(resultReceiver);
  await cameraEnhancer.open();
  await router.startCapturing("ReadSingleBarcode");
})

let startScanBtn = document.getElementById("StartScanning"); // double check the ID of the button
startScanBtn.addEventListener("click", async function () {
  let scanner = await Dynamsoft.DBR.BarcodeScanner.createInstance();
  scanner.onFrameRead = (results) => {
    console.log(results);
  };
  scanner.onUniqueRead = (txt, result) => {
    alert(txt);
  };
  await scanner.show();
});