function hide_element(nodeId)
{
    var node = document.getElementById(nodeId);
    if (node)
    {
        node.style.display = 'none';
    } 
}
 
function show_element(nodeId)
{
    var node = document.getElementById(nodeId);
    if (node)
    {
        node.style.display = 'block';
    } 
}