7 – how to call handler on every ajax request

I have created a handler for every submit request using $form(‘#submit’)() = ‘MYMODULE_form_submit_handler’ now the problem is this doesnt works on Ajax submit, or page call backs functions. i want to log everything that is happening on every insert,update/delete in admin area

$form('button') = array(
    '#type' => 'button',
    '#value' => t('Save'),
    '#attributes' => array(
        'onclick' => 'return false;',
        'class' => array('form-submit', 'rights-form-submit')

Where ‘rights-form-submit’ is a class that directs this button to AJAX call from javascript. i want to call hook on success / failure of request