anchor.diff:      el.empty(); // remove old options
   
       console.log(address);
  -    if(branches[address] != undefined) {
  +    if(branches[address] != null) {
         fill_options(branches[address], el);
         return;
       }
  
positive.code: </script>
  
  <script>
    var branches = {};
    var request = null;
    function fetch_branches (address_field) {
  
negative.code: 
  
  <script>
    function show_branches () {
      var scm_type_field = document.getElementById("repository_scm_type");
      var index = scm_type_field.selectedIndex;
      var option = scm_type_field.options[index];
  
  