auiu-ajax.php

<?php
class AUIU_Ajax {
    function __construct() {
        add_action( 'wp_ajax_nopriv_auiu_get_child_cats', array($this, 'get_child_cats') );
        add_action( 'wp_ajax_auiu_get_child_cats', array($this, 'get_child_cats') );
        add_action( 'wp_ajax_nopriv_auiu_feat_img_del', array($this, 'featured_img_delete') );
		add_action( 'wp_ajax_auiu_feat_img_del', array($this, 'featured_img_delete') );
        add_action( 'wp_ajax_nopriv_auiu_featured_img', array($this, 'featured_img_upload') );
		add_action( 'wp_ajax_auiu_featured_img', array($this, 'featured_img_upload') );
    }
    /**
     * Returns child category dropdown on ajax request
     */
    function get_child_cats() {
        $parentCat = $_POST['catID'];
        $result = '';
        if ( $parentCat < 1 )
            die( $result );
        if ( get_categories( 'taxonomy=category&child_of=' . $parentCat . '&hide_empty=0' ) ) {
            $result .= wp_dropdown_categories( 'show_option_none=' . __( '-- Select --', 'auiu' ) . '&class=dropdownlist&orderby=name&name=category[]&id=cat-ajax&order=ASC&hide_empty=0&hierarchical=1&taxonomy=category&depth=1&echo=0&child_of=' . $parentCat );
        } else {
            die( '' );
        }
        die( $result );
    }
    /**
     * Delete a featured image via ajax
     *
     * @since 0.8
     */
    function featured_img_delete() {
        check_ajax_referer( 'auiu_nonce', 'nonce' );
        $attach_id = isset( $_POST['attach_id'] ) ? intval( $_POST['attach_id'] ) : 0;
        $attachment = get_post( $attach_id );
        //post author or editor role
        if ( get_current_user_id() == $attachment->post_author ) {
            wp_delete_attachment( $attach_id, true );
            echo 'success';
        }
        exit;
    }
    /**
     * Upload Featured image via ajax
     *
     * @since 0.8
     */
    function featured_img_upload() {
        check_ajax_referer( 'auiu_featured_img', 'nonce' );
	    $upload_data = array(
            'name' => $_FILES['auiu_featured_img']['name'],
            'type' => $_FILES['auiu_featured_img']['type'],
            'tmp_name' => $_FILES['auiu_featured_img']['tmp_name'],
            'error' => $_FILES['auiu_featured_img']['error'],
            'size' => $_FILES['auiu_featured_img']['size']
        );
		$attach_id = auiu_upload_file( $upload_data );

		if ( $attach_id ) {
            $html = auiu_feat_img_html( $attach_id );
            $response = array(
                'success' => true,
                'html' => $html,
            );
            echo json_encode( $response );
            exit;
        }
        $response = array('success' => false);
        echo json_encode( $response );
        exit;
    }
}
$auiu_ajax = new AUIU_Ajax();