Wordpress - How to add a Capability to a User Role?
You can use WP_Role class,
// get the the role object
$role_object = get_role( $role_name );
// add $cap capability to this role object
$role_object->add_cap( $capability_name );
// remove $cap capability from this role object
$role_object->remove_cap( $capability_name );
So to address your original question about how to enable Admins to enter SCRIPT and IFRAME tags into post content, you're looking for the 'unfiltered_html' capability, which in Multisite is only granted to Super Admins.
// get the the role object
$admin_role = get_role( 'administrator' );
// grant the unfiltered_html capability
$admin_role->add_cap( 'unfiltered_html', true );
or you can run this once in your functions:
/* Roles & Capabilities */
add_role('professional', 'Professional User', array(
'read' => true, // True allows that capability, False specifically removes it.
'edit_posts' => true,
'delete_posts' => true,
//'edit_published_posts' => true,
//'publish_posts' => true,
//'edit_files' => true,
'upload_files' => true //last in array needs no comma!
));
In order to allow another role other than Super Admin or Admin (depending if the Wordpress installation is a network/MU instance or not) to add unfiltered html to a post or comment Wordpress’ KSES filter must be removed.
Check if a user has a particular capability.
if ( current_user_can( 'unfiltered_html' ) ) { … }
If so than remove KSES
kses_remove_filters();
This functionality is already wrapped up in unfiltered-mu, allowing admins and editors to add unfiltered html.