mail" class="form-control email" type="text" maxlength="50" placeholder="请输入邮箱">
                                <span class="input-group-addon"><i class="fa fa-envelope"></i></span>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
            <div class="row">
                <div class="col-sm-6">
                    <div class="form-group">
                        <label class="col-sm-4 control-label is-requir