根据下拉列表隐藏行

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

<table>
  <tr id="row1">
    <td>Row 1</td>
  </tr>
  <tr id="row2">
    <td>Row 2</td>
  </tr>
  <tr id="row3">
    <td>Row 3</td>
  </tr>
</table>

#row1, #row2, #row3 {
  display: none;
}

document.getElementById("dropdown").addEventListener("change", function() {
  var selectedOption = this.value;
  
  if (selectedOption === "option1") {
    document.getElementById("row1").style.display = "table-row";
    document.getElementById("row2").style.display = "none";
    document.getElementById("row3").style.display = "none";
  } else if (selectedOption === "option2") {
    document.getElementById("row1").style.display = "none";
    document.getElementById("row2").style.display = "table-row";
    document.getElementById("row3").style.display = "none";
  } else if (selectedOption === "option3") {
    document.getElementById("row1").style.display = "none";
    document.getElementById("row2").style.display = "none";
    document.getElementById("row3").style.display = "table-row";
  }
});