var viewer;
function openWindow(file, prop) {
    if (top.opener) {
        window.name = "viewer2";
    }

    if (viewer) {
        if (viewer.closed) {
            viewer = window.open(file, 'viewer', prop);
            viewer.focus();
        } else {
            viewer.close();
            viewer = window.open(file, 'viewer', prop);
            viewer.focus();
        }
    } else {
        viewer = window.open(file, 'viewer', prop);
        viewer.focus();
    }
}
function Nav(URL) {
    window.location.href = URL;
}