<picker bindchange='bindPickerDatewokrtime' mode='date' start="1900-01-01" end="{{gongyongtime}}" value='{{worktime}}'>

          <view>

            <view class="fontcolorad">开始工作日期:</view>{{worktime}}

            <input style="display:none" value="{{worktime}}" name="startWorkYear"></input>

          </view>

        </picker>

如题，现在的格式是 1998-07-05

现在只想要 1998-07  天不要了，有木有办法