function get_events(url){
  url = "http://localhost:3000/get_events?workshop_id="+$("#workshop_selector")[0].value+".json";
  if ($("#workshop_selector")[0].value == ''){
    url = "http://localhost:3000/get_events?.json";
  }
  $.getJSON(url,function(data){
    $("#workshop_registration_workshop_location_id").empty();
    $.each(data,function(entryIndex,entry){
      var html = '<option value="'+entry.id+'" >';
      html+=entry.city ;
      html+='</option>';
      $("#workshop_registration_workshop_location_id").append(html);
    });
  });
}