问无法使用ajax提交表单时收到警报

EN

if(results.size() >3)
{
   System.out.println("Too many people asked for that day off");
   return new ModelAndView("request");

}
else
{
    Request request = new Request();
    request.setDate(newDate);
    request.setNumDays(numDays);
    request.setReason(reason1);

    ModelAndView mv = new ModelAndView("successRequest");
    mv.addObject("request", request);

    requestService.save(request);
        return mv;
}

$('#form').submit(function(e)
{   
     $.ajax({
     type:'POST',
     url:"/request",
     data:$(this).serialize(),
     error: function(){
      window.alert("Too many people have asked for that day off");
      console.log("Error");
     }
});     
});