function displayPopup(what) {
    document.getElementById(what).style.display = "block";
    //if (document.getElementById('PageMask')) document.getElementById('PageMask').style.display = "block";
}

function hidePopup(what) {
    document.getElementById(what).style.display = "none";
    //if (document.getElementById('PageMask')) document.getElementById('PageMask').style.display = "none";
}