doba=3000
pocet = 5
rotator=1

function rotate() {

document.getElementById('top1').className='block-off';
document.getElementById('main2_1').className='';
document.getElementById('my_gallery1').className='block-off';

document.getElementById('top2').className='block-off';
document.getElementById('main2_2').className='';
document.getElementById('my_gallery2').className='block-off';

document.getElementById('top3').className='block-off';
document.getElementById('main2_3').className='';
document.getElementById('my_gallery3').className='block-off';

document.getElementById('top4').className='block-off';
document.getElementById('main2_4').className='';
document.getElementById('my_gallery4').className='block-off';

document.getElementById('top5').className='block-off';
document.getElementById('main2_5').className='';
document.getElementById('my_gallery5').className='block-off';

document.getElementById('top'+rotator+'').className='block-on';
document.getElementById('main2_'+rotator+'').className='highlighted';
document.getElementById('my_gallery'+rotator+'').className='block-on';
rotator = rotator + 1
if (rotator>pocet) {rotator=1;}
}

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