var is = new Array();
var imaxs = new Array();

function set_p(i, d)
{
 var n = is[i] + d;
 if (n < 0)
  n = imaxs[i];
 if (n == imaxs[i])
  n = 0;

 $('#p_'+ i + '_' + is[i]).addClass('hidden');
 is[i] = n;
 $('#p_'+ i + '_' + is[i]).removeClass('hidden');
 $('#i_'+i).html(n-0+1);
}