function rollOver(obj){
  var check = obj.src.split('_over');
  if(check.length > 1) return;
  var spl = obj.src.split('.');
  var ujsrc = '';
  var i=0;
  
  for(i=0; i<spl.length; ++i){
    if(i == (spl.length - 1 )) ujsrc += '_over.';
    ujsrc += spl[i];
    if(i < (spl.length - 2 )) ujsrc += '.';
  }

  obj.src = ujsrc;
}

function rollOut(obj){
  if(obj.id == 'akt') return;
  var spl = obj.src.split('_over');
  obj.src = spl[0]+spl[1];
}