I was trying to make a tester for a handler to open an app, and if the app isn’t there, then open the download page. But with the code I have, it doesn’t work exactly how I would like it. The problem appears when the app isnt istalled. Maybe someone can help me in the right direction.

<li onclick="openWebexContent()" class="li-slider">
WBX
</li>

function openWebexContent() {
    var appURL = "webex://";
    var fallbackURL = "https://webex.com/downloads.html";
    var appOpened = true;

    var iframe = document.createElement('iframe');
    iframe.style.display = 'none';
    iframe.src = appURL;
    document.body.appendChild(iframe);

    setTimeout(function () {
        if (!appOpened) {
            document.body.removeChild(iframe);
            var downloadConfirmation = confirm("Webex kon niet worden geopend! Klik op OK om het te downloaden.");
            if (downloadConfirmation) {
                window.open(fallbackURL);
            } else {
                alert("eeuhm een error");
            }
        }
    }, 1000);

    iframe.onload = function () {
        appOpened = false;
    };
}