值为null时如何隐藏表行

<tr class="hide-row">
  <td>...</td>
  <td>...</td>
</tr>

<style>
.hide-row {
  display: none;
}
</style>

<tr id="row1">
  <td>...</td>
  <td>...</td>
</tr>

<script>
var row = document.getElementById("row1");
row.style.display = "none";
</script>

<?php
$value = null;

if ($value !== null) {
  echo "<tr>";
  echo "<td>...</td>";
  echo "<td>...</td>";
  echo "</tr>";
}
?>