<DatePicker  id="startTime" v-on:on-change="getTaxDate" type="month" placement="bottom-start"
                                    placeholder="选择日期"></DatePicker>
                            <!-- <input class="timeInput" type="text" id="startTime"> -->
                            <span>—</span>
                            <DatePicker v-on:on-change="getTaxEndDate" type="month" placement="bottom-start"
                                    placeholder="选择日期" id="endTime"></DatePicker>

methods: {
            getTaxDate: function (date) {
                this.startTime = date
            },
            getTaxEndDate: function (date) {
                this.endTime = date
            }
}

 data () {
            return {
                id: 'echartsBarType',
                id2: 'echartsPieType',
                option: {},
                option2: {},
                startTime: '',
                endTime: ''
            }
        },

watch:{
　　　　startTime() {
                if (this.startTime) {
                   console.log('开始时间',this.startTime)
                } else {
                    this.actTaxDate = '';
                }
            }
}

        computed: {
            timeChange() {
                const { startTime, endTime } = this
                return {
                    startTime,
                    endTime
                }
            }
        },

        watch: {
            timeChange: {
                handler: function(val) {
                    console.log('address change: ', val)
                },
                deep: true
            }
        },