form表单提交不刷新

<form action="${basePath}/teacher/problem/upPPt" method="post" enctype="multipart/form-data" target="nm_iframe">
                    <a href="javascript:;" class="file">选择文件
                        <input type="file" name="file" id="ppt">
                    </a>
                    <input type="text" value="${courseNote.id }" name="courseNoteId" style="display:none;" >
                    <button class="ui button"  type="submit">上传</button>
                </form>
                <iframe id="id_iframe" name="nm_iframe" style="display:none;"></iframe>

iframe中的name与form表单中的target相同