如何根据另一个下拉列表的选择将数组动态添加到下拉列表中？

<select id="select1" onchange="updateDropdown()">
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

<select id="select2"></select>

var options = {
  option1: ["Option 1-1", "Option 1-2", "Option 1-3"],
  option2: ["Option 2-1", "Option 2-2", "Option 2-3"],
  option3: ["Option 3-1", "Option 3-2", "Option 3-3"]
};

function updateDropdown() {
  var select1 = document.getElementById("select1");
  var select2 = document.getElementById("select2");
  var selectedValue = select1.value;
  
  // 清空第二个下拉列表的选项
  select2.innerHTML = "";
  
  // 根据选择的值动态添加选项
  for (var i = 0; i < options[selectedValue].length; i++) {
    var option = document.createElement("option");
    option.text = options[selectedValue][i];
    select2.add(option);
  }
}

window.onload = function() {
  updateDropdown();
};