如何根据检索到的php值更改单元格颜色？

<table>
  <tr>
    <td id="cell1"></td>
    <td id="cell2"></td>
    <td id="cell3"></td>
  </tr>
</table>

<?php
$value = // 获取到的PHP值

if ($value == "条件1") {
    echo "<script>document.getElementById('cell1').style.backgroundColor = 'red';</script>";
} elseif ($value == "条件2") {
    echo "<script>document.getElementById('cell2').style.backgroundColor = 'blue';</script>";
} else {
    echo "<script>document.getElementById('cell3').style.backgroundColor = 'green';</script>";
}
?>