How to access a specific pjax block?

Question

Yii

There is a registration form wrapped in pjax with id = 'pjax1'. Inside nested pjax with id = 'pjax2' to set a specific field.
How to hang an event on a specific pjax?
This is how it turns out for all pjax's on the page
$(document).on('pjax:complete', function() {
alert('I divide');
});