doba=5000
pocet = 5
rotator=1

function rotate() {

document.getElementById('clanok-photo1').className='block-off';
document.getElementById('row-1').className='';

document.getElementById('clanok-photo2').className='block-off';
document.getElementById('row-2').className='';

document.getElementById('clanok-photo3').className='block-off';
document.getElementById('row-3').className='';

document.getElementById('clanok-photo4').className='block-off';
document.getElementById('row-4').className='';

document.getElementById('clanok-photo5').className='block-off';
document.getElementById('row-5').className='';

document.getElementById('clanok-photo'+rotator+'').className='block-on';
document.getElementById('row-'+rotator+'').className='activ';
rotator = rotator + 1
if (rotator>pocet) {rotator=1;}
}

window.setInterval("rotate();",5000)