check_ajax_referer action-hook . WP 2.1.0

Fires once the Ajax request has been validated or not.

Usage

add_action( 'check_ajax_referer', 'action_function_name_5439', 10, 2 );
function action_function_name_5439( $action, $result ){
	// action...
}

$action(string)

The Ajax nonce action.

$result(false/int)

False if the nonce is invalid, 1 if the nonce is valid and generated between
0-12 hours ago, 2 if the nonce is valid and generated between 12-24 hours ago.

Where the hook is called

do_action( 'check_ajax_referer', $action, $result );

Where the hook is used (in WP core)