function toUp(){
}
function toDown(){
}

function prepare(){
var marg = 1;
var prRotCount = 9;

document.getElementById('arr_bot').onclick = function(){
	last = marg + prRotCount;
	if(document.getElementById('it_' + last)){
	document.getElementById('it_' + marg).style.display = 'none';
	
	marg++;
	}
}

document.getElementById('arr_top').onclick = function(){
curr = marg -1;
if(curr >= 1){
document.getElementById('it_' + curr).style.display = '';
marg--;
}

}

}
window.onload = prepare;