function displayOverlay() {
    adjustOverlaySize();
    showDiv("overlay");
    showDiv("overlayContent");
}

function adjustOverlaySize() {
    var lHeight = document.getElementById("page").scrollHeight;
    //alert(lHeight);
    var lOverlay = document.getElementById("overlay");
    lOverlay.style.height = lHeight + 'px';
}

function showDiv(pName) {
    var el = document.getElementById(pName);
    el.style.visibility = (el.style.visibility == "visible") ? "hidden" : "visible";
}