Comment out HTML and PHP together

I agree that Pascal's solution is the way to go, but for those saying that it adds an extra task to remove the comments, you can use the following comment style trick to simplify your life:

<?php /* ?>
<tr>
      <td><?php echo $entry_keyword; ?></td>
      <td><input type="text" name="keyword" value="<?php echo $keyword; ?>" /></td>
    </tr>
    <tr>
      <td><?php echo $entry_sort_order; ?></td>
      <td><input name="sort_order" value="<?php echo $sort_order; ?>" size="1" /></td>
    </tr>
<?php // */ ?>

In order to stop the code block being commented out, simply change the opening comment to:

<?php //* ?>

Instead of using HTML comments (which have no effect on PHP code -- which will still be executed), you should use PHP comments:

<?php /*
<tr>
      <td><?php echo $entry_keyword; ?></td>
      <td><input type="text" name="keyword" value="<?php echo $keyword; ?>" /></td>
    </tr>
    <tr>
      <td><?php echo $entry_sort_order; ?></td>
      <td><input name="sort_order" value="<?php echo $sort_order; ?>" size="1" /></td>
    </tr>
*/ ?>

With that, the PHP code inside the HTML will not be executed; and nothing (not the HTML, not the PHP, not the result of its non-execution) will be displayed.

Just one note: you cannot nest C-style comments... which means the comment will end at the first */ encountered.