Javascript 从下拉菜单中选择新月份将清除Vuejs中的日期下拉列表

我有三个下拉菜单，分别代表出生日期、月份和年份：

<input-select
  id="dateOfBirth"
  label="Day"
  :name="'dateOfBirth' | hashcode"
  :option-default="select dat"
  :option-list="birthDates"
  :v-model="birthdate"
  :value="birthdate"</input-select> 

<input-select
  id="monthOfBirth"
  label="Month"
  :name="'monthOfBirth' | hashcode"
  :option-default="select month"
  :option-list="birthMonth"
  v-model="birthmonth"
  :value="birthMonth"></input-select> 

<input-select 
  id="yearOfBirth"
  label="Year"
  :name="'yearOfBirth' | hashcode"
  :option-list="birthYears"
  :option-default="select year"
  v-model="birthyear"
  :value="birthyear"
></input-select>

---

确保您的
v-model
出生日期
未在代码中的任何其他位置更新。用计算机或手表。这可能就是原因。另外，我注意到您同时使用了
v-model
和
：value
。尝试删除
：值

data: function () {
    return {
    //initiating the array which would show the dates
    birthdate:[],
    numDates:''
...
  methods: {
    //the function that would repopulate the birthdate[] array
    birthdateValueList(){
      //erasing the values of the existing array
      this.birthdates = []
      //adding new values
      let i = 1;
      //numDates is defined in another function based on the month selected, please see below
      while (i <= this.numDates){
        this.birthdates.push(i);
        i ++;
      }
...
  // watching the birthmonth drop down and setting the number days for that month
  // this is where we define numDates
  watch: {
    birthmonth:function(){
      if(this.birthmonth === "April" || this.birthmonth === "June" || this.birthmonth === "September" || this.birthmonth === "November"){
        this.numDates = 30
      }else if (this.birthmonth === "February" && this.leapYear){
          this.numDates = 29
        }
         else if(this.birthmonth === "February" && !this.leapYear){
          this.numDates = 28
      }
      else {
        this.numDates = 31
      }
...
  // and then a computed property to do some formatting and returning the final array
  computed: {
    birthDates: function(){
      var list = JSON.parse(JSON.stringify(this.birthdates));
      var birthdateDates = this.generateNewList(list);
      return birthdateDates;
    },