function showLayer(layerName)
{
    if (document.getElementById) // Netscape 6 and IE 5+
    {
        var targetElement = document.getElementById(layerName);
        targetElement.style.display = 'block';
    }
}

function hideLayer(layerName)
{
    if (document.getElementById) 
    {
        var targetElement = document.getElementById(layerName);
        targetElement.style.display = 'none';
    }
}
		
function toggle_visibility(id) {
    var e = document.getElementById(id);

    if(e.style.display == '')
        e.style.display = 'block';
    else
        if(e.style.display == 'none')
            e.style.display = 'block';
    else
        e.style.display = 'none';
}