//1.只能选择今天之后的日期
data (){
   return {
       pickerOptions: {
          disabledDate(time) {
            return time.getTime() < Date.now();
          }
        },  
   }     
}

//2、开始日期不得选择早于今天
pickerOptions:{  //写在data函数里
        disabledDate:time =>{
          return time.getTime() < Date.now() - 8.64e7;
        }
      },

:picker-options="pickerOptions"   //绑定在组件里面

//3、只能选择今天以及以前的日期
 pickerOptions: {
          disabledDate(time) {
            return time.getTime() > Date.now() - 8.64e6
          }
        }, 

//4.只能选择今天之前的日期
data (){
   return {
       pickerOptions0: {
          disabledDate(time) {
            return time.getTime() > Date.now();
          }
        },  
   }     
}

//5.设置选择三个月之前到今天的日期
data (){
   return {
       pickerOptions0: {
          disabledDate(time) {
            let curDate = (new Date()).getTime();
            let three = 90 * 24 * 3600 * 1000;
            let threeMonths = curDate - three;
            return time.getTime() > Date.now() || time.getTime() < threeMonths;;
          }
        }, 
   }    
}