在选择标签上显示/隐藏div

<select id="selectTag">
  <option value="option1">选项1</option>
  <option value="option2">选项2</option>
  <option value="option3">选项3</option>
</select>

<div id="div1" style="display: none;">
  这是选项1对应的内容。
</div>

<div id="div2" style="display: none;">
  这是选项2对应的内容。
</div>

<div id="div3" style="display: none;">
  这是选项3对应的内容。
</div>

var selectTag = document.getElementById("selectTag");

selectTag.addEventListener("change", function() {
  var selectedValue = selectTag.value;

  if (selectedValue === "option1") {
    document.getElementById("div1").style.display = "block";
    document.getElementById("div2").style.display = "none";
    document.getElementById("div3").style.display = "none";
  } else if (selectedValue === "option2") {
    document.getElementById("div1").style.display = "none";
    document.getElementById("div2").style.display = "block";
    document.getElementById("div3").style.display = "none";
  } else if (selectedValue === "option3") {
    document.getElementById("div1").style.display = "none";
    document.getElementById("div2").style.display = "none";
    document.getElementById("div3").style.display = "block";
  }
});