function showhide(id,height)
{
    image = document.getElementById(id+"image");
    element = document.getElementById(id);
    if(document.getElementById(id).style.visibility=="visible")
    {
        image.src = "./images/folder_close.png";
        element.style.visibility="hidden";
        element.style.height = "0px";
    } else {
        image.src = "./images/folder_open.png";
        element.style.visibility="visible";
        element.style.height = height+"px";
    }
}