unsplash-logo Alex

Troubleshooting WordPress AJAX

Published 2018-05-28

I was working with some AJAX functionality a while back and started writing down the problems and solutions I ran across so they were all in one place. Basically, this post is for my future self. I hope you find it useful as well. :)

Specific Problems

Function Always Returns 0

If you’re getting a “0” as the response from an AJAX call in the admin, it’s most likely one of three things:

403 Forbidden Error

Check the Nonce. You probably copied it from another function and it’s checking the wrong one.

Helpful Tip

The PHP function that processes the AJAX request has to echo something and should end with:


You can use that to return something you want to see, like what data was passed to the function.

To check an array, use this instead:


Share this post!

Check out these most recent posts:

How to Add a Class to a Metabox

Toggling the visibility of a metabox using a form requires the metabox to have a custom class. This is how to add custom classes to a metabox.

ArtistDataPress Expiration

In case you haven't heard, ArtistData is shutting down, so the ArtistDataPress plugin will also be shutting down as of October 14.

Avoiding get_theme_mod Errors

If you're getting an error related to the get_theme_mod function, the solution is simpler than you think. Check out this solution.