can someone tell me how can I make empty value, that if nothing is in list of select, show "n/a"
demo
https://codepen.io/Turqus/pen/wPrKrr?editors=1010
template
    <div ng-app="test" ng-controller="select">
  <select class="form-control" ng-model="selectedBoard" ng-change="changeBoard(selectedBoard)">
     <option ng-repeat="item in boards" value="{{$index}}">{{$index}}</option>   
 </select>
 <select class="form-control" ng-model="selectedList">
   <option ng-repeat="item in downloadedLists" value="{{$index}}">{{$index}}</option> 
 </select>                  
</div>