doba=3000;
pocet = 5;
rotator_hc=1;

function rotate_hc() {

document.getElementById('hlavny-clanok1').className='block-off';
document.getElementById('main2_1').className='';


document.getElementById('hlavny-clanok2').className='block-off';
document.getElementById('main2_2').className='';


document.getElementById('hlavny-clanok3').className='block-off';
document.getElementById('main2_3').className='';


document.getElementById('hlavny-clanok4').className='block-off';
document.getElementById('main2_4').className='';


document.getElementById('hlavny-clanok5').className='block-off';
document.getElementById('main2_5').className='';


document.getElementById('hlavny-clanok'+rotator_hc+'').className='block-on';
document.getElementById('main2_'+rotator_hc+'').className='highlighted';

rotator_hc = rotator_hc + 1;
if (rotator_hc>pocet) {rotator_hc=1;}
}

window.setInterval("rotate_hc();",3000)