var img = [];
  var txt = [];
  var num = 0;
  var start = 1;

function sdvig()
{
for( n=1; n<=3; n++)
  {
    num = parseFloat(start) + parseFloat(n) -1;
    if(num>max) num = parseFloat(num) - parseFloat(max);
    document.getElementById('img_' + n).style.background = 'url(\'' + img[num] + '\')';
    document.getElementById('img_' + n).innerHTML = txt[num] ;
  };
}

function img_up()
{
  start--;
  if(start<1) start = max;
  sdvig();
}

function img_down()
{
  start++;
  if(start>max) start = 1;
  sdvig();
}