Ajax调用中的TypeError

Question

我在Laravel 5中的Ajax调用上遇到以下错误：

TypeError：＆＃39; stepUp＆＃39;调用了一个没有实现接口HTMLInputElement的对象。

  

d = []，E =函数（A，B）{B = n.isFunction（b）中的b（）：空== B＆＃34;＆＃34;：？B，

表格如下：

<form id="comment_form">
    <input type="textarea" class="form-control_comment" id="comment" placeholder="Type your comment here...">
    <input type="hidden" name="uid" id="uid" value="{{$user->id}}">
    <input type="hidden" name="pid" id="pid" value="{{$post->id}}">
    <input type="hidden" id="token" value="{{$csrf_token()}}">
    <button type="button" class="btn btn-sm btn-success" id= "comment_button">Submit</button>
</form>

Ajax部分：

<script>

   $("#comment_button").click(function(e){


             e.preventDefault();
             var token = $("#token").val();
             var a= $("#comment").val();
             var uid= $("#uid").val();
             var url = "<?php echo Request::root();?>";



            $.ajax({

                url: url+"post/comment_action",
                type: "POST",
                async: false,
                data: {newComment:a, uid:uid, pid:pid, _token: token},

                success: function (newResult){


                    if(newResult!="")
                    {
                        newResult= JSON.parse(newResult);
                        $("#all_responses").append(newResult);
                    }


                }
            }).error(function()
            {
                alert("Error");
            });

        });

</script>

在routes.php中：

Route::post('post/comment_action', array('as'=>'post/comment_action', 'uses'=>'PostController@postComment_action'));

PostController中的动作部分：

 public function postComment_action()
{

    if(Auth::check())
    {
        if(Request::ajax())
        {
            $inputs= Input::all();

        }

        $new_comment= $inputs['newComment'];
        $uid= $inputs['uid'];
        $pid= $inputs['pid'];
        $com= new Comment;
        $com->content= $new_comment;
        $com->userId= $uid;
        $com->postId= $pid;
        $com->save();

        $data= array();

        $all_comments= Comment::where('postId', $pid)->first();
        $u= User::where('id', $uid);

        foreach($all_comments as $coms)
        {
            $data= $coms->content;
        }

        $data= json_encode($data);
        echo $data;
    }
    else
    {
        return Redirect::route('signin_user')->withErrors("You must sign in to perform this action");
    }

}

非常感谢任何帮助：）