How to use admin_body_class filter in WordPress

admin_body_class filter

This filter differs from the ‘post_class’ and ‘body_class’ filters in two important ways:

To use the admin_body_class filter, first, you have to register it using add_filter. You can write this code into the functions.php of your activated theme or in a custom WordPress Plugin.

We at WePlugins always prefer to create a custom WordPress Plugin while using hooks so nothing breaks when you update your WordPress Theme in the future.

In the below live example, we have defined a function weplugins_modify_admin_body_class_defaults which takes 1 parameter and we registered using add_filter. The first parameter admin_body_class is the name of the hook, the second parameter weplugins_modify_admin_body_class_defaults is the name of the function which needs to be called, the third parameter is the priority of calling the hook if the same hook is used multiple times and the last parameter is the number of arguments (if any) to be passed in the registered function.

Sometimes, you have to remove a registered hook so you can use remove_filter to remove the admin_body_class filter.

Parameters

Below the 1 parameter is required to use this hook.

• $classes : (string) Space-separated list of CSS classes.

Live Example 1: Adding Custom Classes

This example demonstrates how to add custom classes to the admin body.

    function weplugins_admin_body_class( $classes ) {
        // Wrong: No space in the beginning/end.
        $classes .= 'my-class1 my-class2';
        // Right: Add a leading space and a trailing space.
        $classes .= ' my-class1 my-class2 ';
        return $classes;
    }
    

Live Example 2: Modifying Admin Body Class

Below is an example of how you can use this hook to modify the admin body class.

    function weplugins_modify_admin_body_class_defaults($classes) {
        // Update the $classes variable according to your website requirements and return this variable. You can modify the $classes variable conditionally too if you want.
        return $classes;
    }
    // add the filter
    add_filter("admin_body_class", "weplugins_modify_admin_body_class_defaults", 10, 1);
    

Live Example 3: Removing a Hook Callback

To remove a hook callback, use the example below.

    remove_filter("admin_body_class", "weplugins_modify_admin_body_class_defaults", 10, 1);
    

Please make sure to provide the same callback function name, priority, and number of arguments while removing the hook callback.