Wordpress XHTML Validation

April 1, 2009, 4:00 pm

Almost immediately after I started my blog I began having difficulties ensuring that my XHTML would validate. Most of the time I could fix it by modifying the code in a plugin that carelessly preventing my XHTML from validating. Almost always it was something trivial (ie using single quotes instead of double quotes or using CAPS in attributes), however one problem I had persisted for quite a while.

These were the errors I was getting:

end tag for element “div” which is not open
XML Parsing Error: Opening and ending tag mismatch: body
XML Parsing Error: Opening and ending tag mismatch: html

After some effort I realized that this error did not appear on the main page or any of the pages. It only appeared when viewing individual posts. After a while I determined that the cause of this was an extra div closing tag. I also realized that the error only occurred when comments were open, which pointed to comments.php as the source of this problem.

After looking through the code my best guess was that these lines were the source of the error:

<?php endif; // If registration required and not logged in ?>
</div>
<?php endif; // if you delete this the sky will fall on your head ?>

Removing the div from the code above seemed to fix the problem in all but one case. Apparently if a page (not a post) has comments enabled, the extra closing tag was needed and not only did validation fail, but it caused the side bar to fall below page. Making the following change seemed to fix all of the errors (as far as I’m aware):

<?php endif; // If registration required and not logged in ?>
<?php if(is_page()) { echo '</div>'; } ?>
<?php endif; // if you delete this the sky will fall on your head ?>

Keeping up with XHTML validation can be tedious, especially when the people who wrote the plugins you are using might not care about validation. Being able to validate your entire site rather than just a page at one time might ease your suffering and it just so happens that such a validator exists: http://htmlhelp.com/tools/validator/