如何限制下拉列表中的值？

<select name="example">
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

<select id="dynamicSelect"></select>

<script>
  const options = ['Option 1', 'Option 2', 'Option 3'];
  const selectElement = document.getElementById('dynamicSelect');

  options.forEach(option => {
    const opt = document.createElement('option');
    opt.value = option.toLowerCase().replace(' ', '_');
    opt.textContent = option;
    selectElement.appendChild(opt);
  });
</script>

<select id="serverSelect"></select>

<script>
  fetch('/api/options')
    .then(response => response.json())
    .then(data => {
      const selectElement = document.getElementById('serverSelect');
      data.forEach(option => {
        const opt = document.createElement('option');
        opt.value = option.value;
        opt.textContent = option.label;
        selectElement.appendChild(opt);
      });
    });
</script>