根据在其他下拉列表中选择的值显示下拉列表

<select id="firstDropdown" onchange="updateSecondDropdown()">
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

<select id="secondDropdown">
  <!-- Options will be dynamically updated based on the selection in the first dropdown -->
</select>

function updateSecondDropdown() {
  var firstDropdown = document.getElementById("firstDropdown");
  var secondDropdown = document.getElementById("secondDropdown");

  // Clear existing options in the second dropdown
  secondDropdown.innerHTML = "";

  // Get the selected value from the first dropdown
  var selectedValue = firstDropdown.value;

  // Based on the selected value, add options to the second dropdown
  if (selectedValue === "option1") {
    var option1 = document.createElement("option");
    option1.value = "option1-1";
    option1.text = "Option 1-1";
    secondDropdown.add(option1);

    var option2 = document.createElement("option");
    option2.value = "option1-2";
    option2.text = "Option 1-2";
    secondDropdown.add(option2);
  } else if (selectedValue === "option2") {
    var option3 = document.createElement("option");
    option3.value = "option2-1";
    option3.text = "Option 2-1";
    secondDropdown.add(option3);

    var option4 = document.createElement("option");
    option4.value = "option2-2";
    option4.text = "Option 2-2";
    secondDropdown.add(option4);
  } else if (selectedValue === "option3") {
    var option5 = document.createElement("option");
    option5.value = "option3-1";
    option5.text = "Option 3-1";
    secondDropdown.add(option5);

    var option6 = document.createElement("option");
    option6.value = "option3-2";
    option6.text = "Option 3-2";
    secondDropdown.add(option6);
  }
}