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: