如何将select元素中的选项与子字符串匹配？

<select id="mySelect">
  <option value="1">Apple</option>
  <option value="2">Banana</option>
  <option value="3">Orange</option>
  <option value="4">Grapes</option>
</select>

<input type="text" id="searchInput">

<script>
const selectElement = document.getElementById('mySelect');
const searchInput = document.getElementById('searchInput');

searchInput.addEventListener('input', function() {
  const searchString = searchInput.value.toLowerCase();

  for (let i = 0; i < selectElement.length; i++) {
    const optionText = selectElement.options[i].text.toLowerCase();
    const optionValue = selectElement.options[i].value;

    if (optionText.includes(searchString)) {
      selectElement.options[i].selected = true; // 设置为选中状态
    } else {
      selectElement.options[i].selected = false; // 取消选中状态
    }
  }
});
</script>