为什么 AJAX 调用、Laravel、JQuery 后 return()->response 不起作用？

Question

JQuery（AJAX 调用）：

$('#frm').validate({
  rules: {
    date1: {
      required: true,
    },
    date2: {
      required: true,
    },  
  },

  submitHandler: function(form) {
            let formD = new FormData(form);
    
    //formD.append(Report_id, $('#inp_2').val());
    
    $.ajax({            
      url: form.action,
      type: form.method,
      data: formD,
      processData: false,
      contentType: false,
      cache: false,
      success:function(data)
      {
        toastr.success(data);
        
      }, 
      error:'', 
    })
  }
});

控制器：

public function product_list_report(Request $request)
{
    $validator = Validator::make($request->all(),[
        "date1" => 'required',
        "date2" => 'required',
    ]);

    if($validator->fails()){return dd("Errored");}
    $f = time().'_'.'mybin_report.csv';
    $headers = array(
        'Content-Type' => 'application/vnd.ms-excel; charset=utf-8',
        'Cache-Control' => 'must-revalidate, post-check=0, pre-check=0',
        'Content-Disposition' => 'attachment; filename='.$f,
        'Expires' => '0',
        'Pragma' => 'public',
    );
    $filename =  public_path("files/".$f);
    if(isset($request->inp_2))
    {
        $data = DB::table('products')
        ->select('products.id as product_id', 'products.name as product_name', 'products.format', 'products.code as product_code', 'products.description', 'products.created_at')
        ->orderBy('products.created_at', 'DESC')
        ->get();
        $columns = array('Product_id', 'Name', 'Format', 'Code', 'Description', 'Created On');

        if (!File::exists(public_path()."/files")) {
            File::makeDirectory(public_path() . "/files");
        }
        //creating the download file
        $file = fopen('php://output', 'w');
        fputcsv($file, $columns);

        $handle = fopen($filename, 'w');
        foreach ($data as $dt) {
            fputcsv($handle, [$dt->product_id, $dt->product_name, $dt->format, $dt->product_code, $dt->description, $dt->created_at,]);    
        }
        $response = array(
            'status' => 'success',
            'response_code' => 200,
            'msg' => 'Successfully created',
        );
    }
    echo json_encode($response);
    fclose($handle);
    return response()->download($filename, $f, $headers);
}

以下是 jquery toastr 响应，这意味着代码已经完成 ajax 调用的成功部分

然后它返回到控制器，当它执行 return response()->download($filename, $f, $headers); 时，文件应该被下载这不是发生这种情况，没有 AJAX 调用，文件就被下载了，我不明白为什么它不起作用。

任何帮助将不胜感激。