Javascript 计算从多个选择中选择了多少

Question

这是HTML:

<select class="form-control selectVitrat" name="PVSuperior" id="PVSuperior">
      <option value="NO">NU</option>
      <option value="YES">DA</option>
    </select>
<select class="form-control selectVitrat" name="PVIntermediar9" id="PVIntermediar9">
      <option value="NO">NU</option>
      <option value="YES">DA</option>
    </select>
<select class="form-control selectVitrat" name="PVIntermediar8" id="PVIntermediar8">
      <option value="NO">NU</option>
      <option value="YES">DA</option>
    </select>

如何计算我从这些多项选择中选择了多少个是？

Answer 1

在JavaScript中，可以用getElementsByTagName得到所有的select。使用 for 循环，您可以检查有多少 select 具有 YES 值：

function checkTotalYes() {
  var selectElements = document.getElementsByTagName("select");
  var count = 0;
  for (var i = 0; i < selectElements.length; i++) {
    if (selectElements[i].value == 'YES')
      count++;
  }
  console.log('Total Yes: ' + count);
}

checkTotalYes();

<select class="form-control selectVitrat" name="PVSuperior" id="PVSuperior" onchange="checkTotalYes()">
  <option value="NO">NU</option>
  <option value="YES">DA</option>
</select>
<select class="form-control selectVitrat" name="PVIntermediar9" id="PVIntermediar9" onchange="checkTotalYes()">
  <option value="NO">NU</option>
  <option value="YES">DA</option>
</select>
<select class="form-control selectVitrat" name="PVIntermediar8" id="PVIntermediar8" onchange="checkTotalYes()">
  <option value="NO">NU</option>
  <option value="YES">DA</option>
</select>

Javascript 计算从多个选择中选择了多少

Javascript count how many selected from multiple selects

html

javascript

select

options