js获取dropdownlist的值

<select id="myDropdown">
  <option value="option1">Option 1</option>
  <option value="option2" selected>Option 2</option>
  <option value="option3">Option 3</option>
</select>

<script>
  const dropdown = document.getElementById('myDropdown');
  const selectedValue = dropdown.value;
  console.log(selectedValue); // 输出: option2
</script>

<select id="myDropdown">
  <option value="option1">Option 1</option>
  <option value="option2" selected>Option 2</option>
  <option value="option3">Option 3</option>
</select>

<script>
  const dropdown = document.getElementById('myDropdown');
  const selectedIndex = dropdown.selectedIndex;
  const selectedValue = dropdown.options[selectedIndex].value;
  console.log(selectedValue); // 输出: option2
</script>

<select id="myDropdown">
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>
<button id="getValueButton">Get Selected Value</button>

<script>
  document.getElementById('getValueButton').addEventListener('click', function() {
    const dropdown = document.getElementById('myDropdown');
    const selectedValue = dropdown.value;
    console.log(selectedValue); // 输出当前选中的值
  });
</script>

window.onload = function() {
  const dropdown = document.getElementById('myDropdown');
  console.log(dropdown.value);
};