How To Avoid Adsense on WordPress 404 pages

In 9 cases out of 10, you’re probably using the custom HTML Widget to add your Adsense code onto your WordPress based site.

That’s fine but it comes with a caveat. What to do when someone navigates to your nicely dressed up 404 page?

The answer is quite simple; we add a filter to widget_text that checks if the page is a 404 page, if so we pass back an empty response. Voilá.

In code (in your templates functions.php file)

add_filter('widget_text','check_404',100);
function check_404($html){
    if (is_404()){
        return '';
    }
    return $html;
}

The above code will hook into the rendering of the adsense code hosting widget, and use the nifty wordpress function is_404() to check whether or not the visitor landed on a 404 page and if that is the case, we send back an empty string, instead of the $html that contains the adsense code.

Simple as pie.