使用每个选项的值更改选择选项的颜色

<select id="colorSelect" onchange="changeColor()">
  <option value="red">Red</option>
  <option value="green">Green</option>
  <option value="blue">Blue</option>
</select>

function changeColor() {
  var select = document.getElementById("colorSelect");
  var selectedColor = select.value;

  var optionElements = select.getElementsByTagName("option");
  for (var i = 0; i < optionElements.length; i++) {
    var option = optionElements[i];
    if (option.value === selectedColor) {
      option.style.color = selectedColor;
    } else {
      option.style.color = "black";
    }
  }
}