Orientation Change Scanner Bug about instascan HOT 9 OPEN

function startCam() {
    var scanner = new Instascan.Scanner({
        video: document.getElementById('preview'),
        scanPeriod: 5,
        mirror: false,
        refractoryPeriod: 10000
    });
    scanner.addListener('scan', function(content) {
        document.getElementById("qrusername").value = content;
        // alert(content);
        //window.open(content);
        //window.location.href=content;
    });
    Instascan.Camera.getCameras().then(function(cameras) {
        if (cameras.length > 0) {
            scanner.start(cameras[1]);
            $('[name="options"]').on('change', function() {
                if ($(this).val() == 1) {
                    if (cameras[1] != "") {
                        scanner.start(cameras[1]);
                    } else {
                        alert('No Front camera found!');
                    }
                } else if ($(this).val() == 2) {
                    if (cameras[0] != "") {
                        scanner.start(cameras[0]);
                    } else {
                        alert('No Back camera found!');
                    }
                }
            });
        } else {
            console.error('No cameras found.');
            alert('No cameras found.');
        }
    }).catch(function(e) {
        console.error(e);
        alert(e);
    });
}