请问一下，为什么我这里设置了上传格式的限制，然后ID也对应了dr_ID 然后为什么我上传图片的时候比如jpg也还可以上传成功啊，。

表单代码：

<div class="layui-form-item layui-form-text">
<label class="layui-form-label col-md-2">*</label>
                        <div style="margin-left: 110px;text-align: left;" class="layui-upload">
                            <input type="hidden" name="data[jlsc]" lay-verify="head" id="dr_jlsc" value="">
                            <button type="button" class="layui-btn layui-btn-primary" id="upload">
                                <i class="layui-icon">&#xe608;</i> 请上传你的简历(仅支持pdf/doc/docx格式)
                            </button>
                        </div>
</div>

JS代码部分：

//layui触发上传按钮---简历上传//
upload.render({
                    elem: '#upload',
                    url: '/index.php?s=ltss&c=shangchuan&m=upload',
                    field: "file_data",
                    data: {
                        file_data: function(){
                            return $('#upload').val();
                        },
                {csrf_token()} : "{csrf_hash()}"
            },
                before: function(obj){
                    //预读本地文件示例，不支持ie8
                    obj.preview(function(index, file, result){
                    });
                },
                done: function(res){
                    if (!res.id){
                        return layer.msg('<span style="color: #fff">'+res.msg+'</span>');
                    }else {
                        if(res.code == 1){
                            $("#head").attr("value", res.id); 
                            return layer.msg('<span style="color: #fff">上传成功</span>');
                        }else{
                            return layer.msg('<span style="color: #fff">上传失败，请重试！</span>');
                        }
                    }
                },
                error: function(){
                    //请求异常回调
                }
            });

PHP代码部分：

<?php namespace Phpcmf\Controllers;
/**
 * 二次开发时可以修改本文件，不影响升级覆盖
 */
class Shangchuan extends \Phpcmf\Home\Module
{
public function upload() {
        $files = $this->request->getFiles();
        $p['exts'] = $files['file_data']->getClientExtension();
        $p['size'] = 100;

        // 验证上传权限
        $rt = \Phpcmf\Service::L('upload')->upload_file([
            'path' => '',
            'form_name' => 'file_data',
            'file_exts' => @explode(',', $p['exts']),
            'file_size' => (int)$p['size'] * 1024 * 1024,
            'attachment' => \Phpcmf\Service::M('Attachment')->get_attach_info(),
        ]);
        if (!$rt['code']) {
            exit(dr_array2string($rt));
        }

        // 附件归档
        $data = \Phpcmf\Service::M('Attachment')->save_data($rt['data']);
        if (!$data['code']) {
            exit(dr_array2string($data));
        }

        // 上传成功
        if (IS_API_HTTP) {
            $data['data'] = [
                'id' => $data['code'],
                'url' => $rt['data']['url'],
            ];
            exit(dr_array2string($data));
        } else {
            exit(dr_array2string(['code' => 1, 'msg' => dr_lang('上传成功'), 'id' => $data['code'], 'info' => $rt['data']]));
        }

    }
}

后台上传字段部分：