function submenu_display(name){
document.getElementById('submenu_omnie').style.display = 'none';
document.getElementById('submenu_uslugi').style.display = 'none';
document.getElementById('submenu_kontakt').style.display = 'none';
document.getElementById('submenu_porady').style.display = 'none';
document.getElementById('submenu_'+name).style.display = 'block';
}