如何根据所选的单选按钮更改下拉列表的值？

<input type="radio" name="options" value="option1"> Option 1
<input type="radio" name="options" value="option2"> Option 2
<input type="radio" name="options" value="option3"> Option 3

<select id="dropdown">
  <option value="default">Please select an option</option>
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

var radioButtons = document.getElementsByName("options");
var dropdown = document.getElementById("dropdown");

for (var i = 0; i < radioButtons.length; i++) {
  radioButtons[i].addEventListener("change", function() {
    dropdown.value = this.value;
  });
}