如何限制文件上传的格式

                    <tr class="rile">

                        <input type="hidden" name="id" readonly value="${one.saleCommodityId}">

                        <td class="title" ><label class="control-label">派工单</label></td>
                        <td  colspan="6">
                            <div class="btn btn-default"style="position: relative; overflow: hidden;width: 100%;margin-top: -6px;">
                                <i class="glyphicon glyphicon-open"  onchange="uploadImg()"></i> 上传派工单
                                <input type="file" name="file" id="tupianfile" style="opacity: 0; position: absolute;
							 top: 12px; right: 0; " class='inpu' multiple="multiple" accept="image/*" onchange="uploadImg()">
                            </div>
                        </td>
                    </tr>

                    <tr class="fo">
                        <td colspan="14" style="text-align: right">


                            <input class="btn btn-primary" id="save" type="submit" value="保存"  />

                            <input class="btn btn-default" id="cancel" type="button" value="取消"
                                   onclick="window.history.back();" />
                        </td>
                    </tr>
                </table>
            </div>

        </form>
</div>

页面显示：

参考地址：https://www.cnblogs.com/yingzi1028/p/8625174.html