function showLayer(layerName) {
    if (document.getElementById) {
        var targetElement = document.getElementById(layerName);
        targetElement.style.display = 'inline';
    }
}
function hideLayer(layerName) {
    if (document.getElementById) {
        var targetElement = document.getElementById(layerName);
        targetElement.style.display = 'none';
    }
}