function search_by_tag(tag) {
  var current_array = $('#q').val().split(", ");

  if($.inArray(tag, current_array) === -1) {
    if ($('#q').val() == "") {
      $('#q').val(tag);
    } else {
      $('#q').val($('#q').val() + ", " + tag);
    }
  perform_search();
  }
}

function perform_search() {
  var term = $('#q').val();
  
  var location = "/foretag";
  
  if(term != "")
    location = location + "?q=" + encodeURIComponent(term);
  
  window.location = location;
}