function showHide(elemId,imgId,forceState)
{
    elem = document.getElementById(elemId);
    img = document.getElementById(imgId); 
    if (elem.style.display == "block") {        
        elem.style.display = "none";
        img.src = '/images/menu-katalog-plus.gif'; 
        img.alt = 'Rozbalit';
        img.title = 'Rozbalit';
    } else {
        elem.style.display = "block";
        img.src = '/images/menu-katalog-minus.gif';
        img.alt = 'Skrýt';
        img.title = 'Skrýt';
    }
}