function rolka(x){
el = document.getElementById(x);
if(el.style.display == 'none')
    el.style.display = 'block';
else
    el.style.display = 'none';
}

function ukryj(x){
el = document.getElementById(x);
    el.style.display = 'none';
}

function pokaz(x){
el = document.getElementById(x);
    el.style.display = 'block';

}