<script src="https://unpkg.com/vue/dist/vue.js"></script>

<div id="calendar">
    <!-- 年份 月份 -->
    <div class="month">
        <ul>
            <!--点击会触发pickpre函数，重新刷新当前日期 @click(vue v-on:click缩写) -->
            <li class="arrow" @click="pickPre(currentYear,currentMonth)">?</li>
            <li class="year-month" @click="pickYear(currentYear,currentMonth)">
                <span class="choose-year">{{ currentYear }}</span>
                <span class="choose-month">{{ currentMonth }}月</span>
            </li>
            <li class="arrow" @click="pickNext(currentYear,currentMonth)">?</li>
        </ul>
    </div>
    <!-- 星期 -->
    <ul class="weekdays">
        <li>一</li>
        <li>二</li>
        <li>三</li>
        <li>四</li>
        <li>五</li>
        <li style="color:red">六</li>
        <li style="color:red">日</li>
    </ul>
    <!-- 日期 -->
    <ul class="days">
        <!-- 核心 v-for循环 每一次循环用<li>标签创建一天 -->
        <li  v-for="dayobject in days">
            <!--本月-->
            <!--如果不是本月  改变类名加灰色-->

            <span v-if="dayobject.day.getMonth()+1 != currentMonth" class="other-month">{{ dayobject.day.getDate() }}</span>

            <!--如果是本月  还需要判断是不是这一天-->
            <span v-else>
          <!--今天  同年同月同日-->
                <span v-if="dayobject.day.getFullYear() == new Date().getFullYear() && dayobject.day.getMonth() == new Date().getMonth() && dayobject.day.getDate() == new Date().getDate()" class="active">{{ dayobject.day.getDate() }}</span>
                <span v-else>{{ dayobject.day.getDate() }}</span>
            </span>

        </li>
    </ul>
</div>

<script>
    var myVue=new Vue({
        el: ‘#calendar‘,
        data: {
            currentDay: 1,
            currentMonth: 1,
            currentYear: 1970,
            currentWeek: 1,
            days: [],
        },
        created: function() {  //在vue初始化时调用
            this.initData(null);
        },
        methods: {
            initData: function(cur) {
                var leftcount=0; //存放剩余数量
                var date;


                if (cur) {
                    date = new Date(cur);
                } else {
                    var now=new Date();
                    var d = new Date(this.formatDate(now.getFullYear() , now.getMonth() , 1));
                    d.setDate(35);
                    date = new Date(this.formatDate(d.getFullYear(),d.getMonth() + 1,1));
                }
                this.currentDay = date.getDate();
                this.currentYear = date.getFullYear();
                this.currentMonth = date.getMonth() + 1;

                this.currentWeek = date.getDay(); // 1...6,0
                if (this.currentWeek == 0) {
                    this.currentWeek = 7;
                }
                var str = this.formatDate(this.currentYear , this.currentMonth, this.currentDay);
                this.days.length = 0;
                // 今天是周日，放在第一行第7个位置，前面6个
                //初始化本周
                for (var i = this.currentWeek - 1; i >= 0; i--) {
                    var d = new Date(str);
                    d.setDate(d.getDate() - i);
                    var dayobject={}; //用一个对象包装Date对象  以便为以后预定功能添加属性
                    dayobject.day=d;
                    this.days.push(dayobject);//将日期放入data 中的days数组 供页面渲染使用


                }
                //其他周
                for (var i = 1; i <= 35 - this.currentWeek; i++) {
                    var d = new Date(str);
                    d.setDate(d.getDate() + i);
                    var dayobject={};
                    dayobject.day=d;
                    this.days.push(dayobject);
                }

            },
            pickPre: function(year, month) {

                // setDate(0); 上月最后一天
                // setDate(-1); 上月倒数第二天
                // setDate(dx) 参数dx为 上月最后一天的前后dx天
                var d = new Date(this.formatDate(year , month , 1));
                d.setDate(0);
                this.initData(this.formatDate(d.getFullYear(),d.getMonth() + 1,1));
            },
            pickNext: function(year, month) {
                var d = new Date(this.formatDate(year , month , 1));
                d.setDate(35);
                this.initData(this.formatDate(d.getFullYear(),d.getMonth() + 1,1));
            },
            pickYear: function(year, month) {
                alert(year + "," + month);
            },

            // 返回 类似 2016-01-02 格式的字符串
            formatDate: function(year,month,day){
                var y = year;
                var m = month;
                if(m<10) m = "0" + m;
                var d = day;
                if(d<10) d = "0" + d;
                return y+"-"+m+"-"+d
            },


        },
    });

</script>