function searchCheck(e) {
    var key;
    if(window.event)
        key = window.event.keyCode;     //IE
    else
        key = e.which;     //firefox   
    
    if(key == 13 && (document.getElementById('header_searchbox_search_input').value.length < 4)) {
        alert('Zadejte prosím více než 3 znaky.'); 
        return false;
    } else return true;
}

function showMenu(menuId) {
    //for (var i = 0; i < 20; i++)
   // if (document.getElementById('submenu' + i) != null) {
        //document.getElementById('submenu' + i).style.display = 'block';
         //document.getElementById(menuId).style.display = 'block';
    //}

}

function hideMenu(menuId) {
      //document.getElementById(menuId).style.display = '';

}

function addClass(element, value) {
    if(!element.className) {
        element.className = value;
    } else {
        newClassName = element.className;
        newClassName+= " ";
        newClassName+= value;
        element.className = newClassName;
    }
}