如何更改一个Input Onchange Selectbox的某些属性

<input type="text" id="myInput" onchange="changeAttributes()">
<select id="mySelect" onchange="changeAttributes()">
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

function changeAttributes() {
  var inputElement = document.getElementById("myInput");
  var selectElement = document.getElementById("mySelect");

  // 更改Input元素的属性
  inputElement.setAttribute("placeholder", "New Placeholder");
  inputElement.style.backgroundColor = "yellow";

  // 更改Select元素的属性
  selectElement.disabled = true;
  selectElement.style.color = "red";
}

<script>
  // 在页面加载时调用changeAttributes()函数
  window.onload = function() {
    changeAttributes();
  };
</script>