当select选项更改时隐藏div

<select id="mySelect">
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

<div id="myDiv">
  This is the content of the div.
</div>

document.getElementById("mySelect").addEventListener("change", function() {
  var selectedOption = this.value;
  
  if (selectedOption === "option1") {
    document.getElementById("myDiv").style.display = "none";
  } else {
    document.getElementById("myDiv").style.display = "block";
  }
});