Onchange根据值填充不同下拉列表

<select id="select1" onchange="populateDropdown()">
  <option value="value1">选项1</option>
  <option value="value2">选项2</option>
  <option value="value3">选项3</option>
</select>

function populateDropdown() {
  var select1 = document.getElementById("select1");
  var selectedValue = select1.value;
  var select2 = document.getElementById("select2");

  // 清空下拉列表的选项
  select2.innerHTML = "";

  // 根据不同的值填充不同的下拉列表选项
  if (selectedValue === "value1") {
    select2.innerHTML += "<option value='option1'>选项1-1</option>";
    select2.innerHTML += "<option value='option2'>选项1-2</option>";
  } else if (selectedValue === "value2") {
    select2.innerHTML += "<option value='option3'>选项2-1</option>";
    select2.innerHTML += "<option value='option4'>选项2-2</option>";
  } else if (selectedValue === "value3") {
    select2.innerHTML += "<option value='option5'>选项3-1</option>";
    select2.innerHTML += "<option value='option6'>选项3-2</option>";
  }
}