Add maxlength attribute to WordPress post title

Question

Is there a hook I can use to append a maxlength attribute to WordPress post titles? I am familiar with sub string function techniques (e.g. http://www.doc4design.com/articles/wordpress-5ways-shorten-titles/), but that's not the same. I've also seen the Limit Post Titles plugin which again works well, but still doesn't enforce the limit.

I want to limit the character length from the onset, e.g.:

<input type="text" autocomplete="off" spellcheck="true" id="title" value="" size="30" maxlength="60" name="post_title" />

Having not found anything on this subject, I assume there might be reasoning as to why this is not a good idea? If so, I would be interested in knowing why.

Answer 1

From looking at the code, I don't think there is a filter you can hook into the add a maxlength attribute to the title field.

You could use javascript to add the attribute:

add_action('admin_footer', function() {
?>
    <script>jQuery('input#title').attr('maxlength', 60);</script>
<?php
});

Note that if you really need to enforce the limit, the maxlength attribute is not sufficient. It's trivial to bypass the restriction.

You'll also need to use the save_post action to validate the title.

I assume there might be reasoning as to why this is not a good idea

It is a good idea to enforce restrictions in the frontend. Letting the user know that their input does not fall within an expected range prior to submitting a form is generally preferable to giving them an error message after submitting the form. You just have to bear in mind that those restrictions must be verified in the backend.