Javascript 检查是否选择了optgroup中的部分或所有选项

我有一个从JSON动态生成的下拉列表。格式如下：

<optgroup id="US" label="United States class="optiongroup>
  <option value="AS">American Samoa</option>
  <option value="AL">Alabama</option>
  ...
  <option value="VI">US Virgin Islands</option>
  <option value="UT">Utah</option>
<optgroup>
<optgroup id="CA" label="Canada" class="optiongroup">
  <option value="AB">Alberta</option>
  <option value="BC">British Columbia</option>
  ...
  <option value="QC">Quebec</option>
  <option value="YT">Yukon Territory</option>
</optgroup>

$(".optiongroup").each(function() {
  var optgroup = $(this);
  $(optgroup.children()).each(function () {
    if ($(this).is(':selected')) {
      statearray.push($(this).attr('value'));
      state_flag = 1; //see if state exists
    } else {
      country_flag = 0; //entire country not selected
  }
}

如果仅选择TN和MS：

country = {[US]}

state = {country: US, statelist: [TN, MS]}

我的第一次尝试是这样的：

<optgroup id="US" label="United States class="optiongroup>
  <option value="AS">American Samoa</option>
  <option value="AL">Alabama</option>
  ...
  <option value="VI">US Virgin Islands</option>
  <option value="UT">Utah</option>
<optgroup>
<optgroup id="CA" label="Canada" class="optiongroup">
  <option value="AB">Alberta</option>
  <option value="BC">British Columbia</option>
  ...
  <option value="QC">Quebec</option>
  <option value="YT">Yukon Territory</option>
</optgroup>

$(".optiongroup").each(function() {
  var optgroup = $(this);
  $(optgroup.children()).each(function () {
    if ($(this).is(':selected')) {
      statearray.push($(this).attr('value'));
      state_flag = 1; //see if state exists
    } else {
      country_flag = 0; //entire country not selected
  }
}

出于某种原因，这对我不起作用

编辑：

---

如果我选择了两个状态，比如TN和AL，它将返回statelist:[Obj Obj]

您需要做更多的检查，看看是否所有状态都被选中：

$(".optiongroup").each(function() {
    var options = $(this).children("option"),
        length = options.length;

    if (options.filter(":selected").length == length) {
        //all are selected, do something!
        country_flag = 1;
        return true; //continue
    } else {
        //Not all selected, so push states
        options.filter(":selected").each(function() {
            statearray.push(this.value);
        });
    }
});

---

看起来不像是在开始推入“statearray”之前将其声明为数组。“国旗”和“国旗”也是一样的。

试试这个。。。希望它能起作用

$("#selectId").children('optgroup').each(function(){                                
    if($(this).children('option').length == $(this).children('option:selected').length){
        // do stuff here when all options were selected under an optgroup   
    }else{
        // do stuff here when all options were NOT selected under an optgroup
    }
});