function hideLayer(layerName)
        {
            if (document.getElementById) 
            {
                var targetElement = document.getElementById(layerName);
                targetElement.style.visibility = 'hidden';
            }
        }

function showLayer(layerName, shadowLayerName)
        {
            if (document.getElementById)
            {
                var targetElement = document.getElementById(layerName);
                var shadowElement = document.getElementById(shadowLayerName);
                targetElement.style.top = shadowElement.style.top;
                targetElement.style.visibility = 'visible';
            }
        }


function hideLayerIframe(layerName)
        {
            if (document.getElementById) 
            {
                var targetElement = parent.document.getElementById(layerName);
                targetElement.style.visibility = 'hidden';
            }
        }