如何在单击时展开html多个选择框

<button onclick="toggleDropdown()">展开选择框</button>
<div id="dropdownContainer">
  <select>
    <option value="option1">选项1</option>
    <option value="option2">选项2</option>
    <option value="option3">选项3</option>
  </select>
  <select>
    <option value="option4">选项4</option>
    <option value="option5">选项5</option>
    <option value="option6">选项6</option>
  </select>
</div>

function toggleDropdown() {
  var dropdownContainer = document.getElementById("dropdownContainer");
  if (dropdownContainer.style.display === "none") {
    dropdownContainer.style.display = "block";
  } else {
    dropdownContainer.style.display = "none";
  }
}

<button onclick="toggleDropdown()">展开选择框</button>