Custom fields at membership checkout for just state.

just_states_pmprorh_init.php

<?php
/**
 * Custom fields at membership checkout for just state.
 *
 */
function just_states_pmprorh_init() {
	global $pmpro_states;
	
    //don't break if Register Helper is not loaded
    if(!function_exists("pmprorh_add_registration_field"))
    {
        return false;
    }
    //define the fields
    $fields = array();
    $fields[] = new PMProRH_Field(
		  'pmp_state',
		  'select',
		  array(
        'label'=>'State',
        'profile'=>true,
        'required' => true,
        'options' => $pmpro_states,
      ));

    //add the fields into a new checkout_boxes are of the checkout page
    foreach($fields as $field)
        pmprorh_add_registration_field(
            "checkout_boxes", // location on checkout page
            $field            // PMProRH_Field object
        );
    //that's it. see the PMPro Register Helper readme for more information and examples.
}
add_action("init", "just_states_pmprorh_init");