element-ui如何设置开始时间小于结束时间

      <el-form-item label="开放时间" prop="placeOpen">
        <el-date-picker
          v-model="defForm.placeOpen"
          type="datetime" value-format="yyyy-MM-dd HH:mm:ss"
          placeholder="选择日期时间" style="width: 200px"
          :picker-options="pickerOptionsStart"
          :disabled="isAble">
        </el-date-picker>
      </el-form-item>
      <el-form-item label="关闭时间" prop="placeClose">
        <el-date-picker
          v-model="defForm.placeClose"
          type="datetime" value-format="yyyy-MM-dd HH:mm:ss"
          placeholder="选择日期时间" style="width: 200px"
          :picker-options="pickerOptionsEnd"
          :disabled="isAble">
        </el-date-picker>
      </el-form-item>

data(){
	return{
        defForm:{
          placeOpen:'',
          placeClose:''
        },
        pickerOptionsStart: {
          disabledDate: time => {
            let endDateVal = this.defForm.placeClose;
            if (endDateVal) {
                return time.getTime() > new Date(endDateVal).getTime();
            }
          }
        },
        pickerOptionsEnd: {
          disabledDate: time => {
            let beginDateVal = this.defForm.placeOpen;
            if (beginDateVal) {
              return (time.getTime()<new Date(beginDateVal).getTime()+1*24*60*60*1000
            );
          }
        }
      },
	}
}