element ui 日期时间选择器格式化只选择年月日时

<el-date-picker

      key='DATETIME'

      v-model="startTime"

      type="datetimerange"

      range-separator="-"

      start-placeholder="开始时间"

      end-placeholder="结束时间"

      :default-time="['00:00:00', '23:00:00']"

       format="yyyyMMddHH"

      value-format="yyyyMMddHH"

      @change="dateChange(startTime)"/>