function showSubMenu(menu) {
    var subMenu = document.getElementById(menu.id + "_sub");
    if (subMenu != null)
        subMenu.style.display = "block";
}

function hideSubMenu(menu) {
    var subMenu = document.getElementById(menu.id + "_sub");
    if (subMenu != null)
        subMenu.style.display = "none";

}

function menuItemOver(event) {
    var menuItem = event.srcElement == null ? event.target : event.srcElement;
    if (menuItem != null && menuItem.className != "menuBar") {
        if (menuItem.tagName == "A")
            menuItem = menuItem.parentNode;
        menuItem.style.backgroundColor = "";
    }
}

function menuItemOut(event) {
    var menuItem = event.srcElement == null ? event.target : event.srcElement;
    if (menuItem != null && menuItem.className != "menuBar") {
        if (menuItem.tagName == "A")
            menuItem = menuItem.parentNode;
        menuItem.style.backgroundColor = "";
    }
}

function debugOut(text) {
    document.getElementById("logo").innerHTML = text;
}

function toggleVisibility(element) {
    if (element.className == "invisible")
        element.className = "";
    else
        element.className = "invisible";
}

///////// teatrography ///////////

function filterByGenre(genreValue)
{
    if(genreValue != null)
    {
        document.getElementById('genreValue').value = genreValue;
        document.teatrographyForm.submit()
    }
}

function filterByYear(yearValue)
{
    if(yearValue != null)
    {
        document.getElementById('yearValue').value = yearValue;
        document.teatrographyForm.submit()
    }
}

function filteByAuthor(authorValue)
{
    if(authorValue != null)
    {
        document.getElementById('authorValue').value = authorValue;
        document.teatrographyForm.submit()
    }
}

function filteByDirector(directorValue)
{
    if(directorValue != null)
    {
        document.getElementById('directorValue').value = directorValue;
        document.teatrographyForm.submit()
    }
}

function filterByAlphabeticalValue(alphabeticalValue)
{
    if(alphabeticalValue != null)
    {
        document.getElementById('alphabeticalFilter').value = alphabeticalValue;
        document.teatrographyForm.submit()
    }
}

function changeLanguage(value)
{
    document.getElementById('language').value = value;
    document.languageForm.submit();
}