) {
      sel=sel+"<optgroup label=\"" + engines[g][0] + "\">" ;
      var values=engines[g][1];
      for(let i = 0; i < values.length; i++) {
	  var v=values[i].toLowerCase();
          sel=sel+"<option value=\"" + v + "\"" +
	      (v==rldefaultengine ? " selected>" : ">") +
	      values[i] + "</option>";
      }
      sel=sel+"</optgroup>";
  }
  enginesel.innerHTML=sel;
  enginesel.addEventListener('change', function() {
      createCookie('runlatex-engine',enginesel.options[enginesel.selectedIndex].v