var objblink = null; // object
var objblinkbis = null;

function lightBlink() {
  objblink = document.getElementById('IS60ONE_8');
  objblinkbis = document.getElementById('IS60ONE_9');
  objblink.style.visibility = 'visible';
  setTimeout(showHide,600);
}

function showHide() {
  if (objblink.style.visibility == 'hidden') {
     objblink.style.visibility = 'visible';
     objblinkbis.style.visibility = 'hidden';
  }
  else {
     objblink.style.visibility = 'hidden';
     objblinkbis.style.visibility = 'visible';
  }
  setTimeout(showHide,600);
}