Is it possible to detect if Microsoft Excel is installed from a Web Application

<script>
var excelInstalled;
try
{
    var excel = new ActiveXObject("Excel.Application");
    excelInstalled = true;
}
catch(e)
{
    excelInstalled = false;
}
alert("excelInstalled: " + excelInstalled);
</script>

function hasOfficePlugin() {
var toCheckExt = ['', '12', '13', '14', '15'], i, n, mt;
    for (i = 0, n = toCheckExt.length; i < n; i++) {
        mt = navigator.mimeTypes['application/x-msoffice' + toCheckExt[i]];
        if (mt && mt.enabledPlugin && mt.enabledPlugin.name) {
            return true;
        }
    }
    return false;
}

var isExcel = window.confirm('dear user if you have Microsoft Excel installed please click on ok, otherwise click on cancel. thank you.');