var oldLayerZIndex;

function disablePageContent(layer) {
    document.getElementById('disablingDiv').zIndex = 1000;
    oldLayerZIndex = layer.zIndex;
    layer.zIndex = 1001;
    document.getElementById('disablingDiv').style.display='block';
}

function enablePageContent(layer) {
    document.getElementById('disablingDiv').zIndex = -1;
    layer.zIndex = oldLayerZIndex;
    document.getElementById('disablingDiv').style.display='none';
}