/wp-content/themes/news/library/functions/customize.php

<?php
/**
 * Functions for registering and setting theme settings that tie into the WordPress theme customizer.  
 * This file loads additional classes and adds settings to the customizer for the built-in Hybrid Core 
 * settings.
 *
 * @package HybridCore
 * @subpackage Functions
 * @author Justin Tadlock <justin@justintadlock.com>
 * @copyright Copyright (c) 2008 - 2012, Justin Tadlock
 * @link http://themehybrid.com/hybrid-core
 * @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 */

/* Load custom control classes. */
add_action( 'customize_register', 'hybrid_load_customize_controls', 1 );

/* Register custom sections, settings, and controls. */
add_action( 'customize_register', 'hybrid_customize_register' );

/* Add the footer content Ajax to the correct hooks. */
add_action( 'wp_ajax_hybrid_customize_footer_content', 'hybrid_customize_footer_content_ajax' );
add_action( 'wp_ajax_nopriv_hybrid_customize_footer_content', 'hybrid_customize_footer_content_ajax' );

/**
 * Loads framework-specific customize control classes.  Customize control classes extend the WordPress 
 * WP_Customize_Control class to create unique classes that can be used within the framework.
 *
 * @since 1.4.0
 * @access private
 */
function hybrid_load_customize_controls() {

	/* Loads the textarea customize control class. */
	require_once( trailingslashit( HYBRID_CLASSES ) . 'customize-control-textarea.php' );
}

/**
 * Registers custom sections, settings, and controls for the $wp_customize instance.
 *
 * @since 1.4.0
 * @access private
 * @param object $wp_customize
 */
function hybrid_customize_register( $wp_customize ) {

	/* Get supported theme settings. */
	$supports = get_theme_support( 'hybrid-core-theme-settings' );

	/* Get the theme prefix. */
	$prefix = hybrid_get_prefix();

	/* Get the default theme settings. */
	$default_settings = hybrid_get_default_theme_settings();

	/* Add the footer section, setting, and control if theme supports the 'footer' setting. */
	if ( is_array( $supports[0] ) && in_array( 'footer', $supports[0] ) ) {

		/* Add the footer section. */
		$wp_customize->add_section(
			'hybrid-core-footer',
			array(
				'title' => 		esc_html__( 'Footer', 'hybrid-core' ),
				'priority' => 	200,
				'capability' => 	'edit_theme_options'
			)
		);

		/* Add the 'footer_insert' setting. */
		$wp_customize->add_setting(
			"{$prefix}_theme_settings[footer_insert]",
			array(
				'default' => 		$default_settings['footer_insert'],
				'type' => 			'option',
				'capability' => 		'edit_theme_options',
				'sanitize_callback' => 	'hybrid_customize_sanitize',
				'sanitize_js_callback' => 	'hybrid_customize_sanitize',
				'transport' => 		'postMessage',
			)
		);

		/* Add the textarea control for the 'footer_insert' setting. */
		$wp_customize->add_control(
			new Hybrid_Customize_Control_Textarea(
				$wp_customize,
				'hybrid-core-footer',
				array(
					'label' => 	esc_html__( 'Footer', 'hybrid-core' ),
					'section' => 	'hybrid-core-footer',
					'settings' => 	"{$prefix}_theme_settings[footer_insert]",
				)
			)
		);

		/* If viewing the customize preview screen, add a script to show a live preview. */
		if ( $wp_customize->is_preview() && !is_admin() )
			add_action( 'wp_footer', 'hybrid_customize_preview_script', 21 );
	}
}

/**
 * Sanitizes the footer content on the customize screen.  Users with the 'unfiltered_html' cap can post 
 * anything.  For other users, wp_filter_post_kses() is ran over the setting.
 *
 * @since 1.4.0
 * @access public
 * @param mixed $setting The current setting passed to sanitize.
 * @param object $object The setting object passed via WP_Customize_Setting.
 * @return mixed $setting
 */
function hybrid_customize_sanitize( $setting, $object ) {

	/* Get the theme prefix. */
	$prefix = hybrid_get_prefix();

	/* Make sure we kill evil scripts from users without the 'unfiltered_html' cap. */
	if ( "{$prefix}_theme_settings[footer_insert]" == $object->id && !current_user_can( 'unfiltered_html' )  )
		$setting = stripslashes( wp_filter_post_kses( addslashes( $setting ) ) );

	/* Return the sanitized setting and apply filters. */
	return apply_filters( "{$prefix}_customize_sanitize", $setting, $object );
}

/**
 * Runs the footer content posted via Ajax through the do_shortcode() function.  This makes sure the 
 * shortcodes are output correctly in the live preview.
 *
 * @since 1.4.0
 * @access private
 */
function hybrid_customize_footer_content_ajax() {

	/* Check the AJAX nonce to make sure this is a valid request. */
	check_ajax_referer( 'hybrid_customize_footer_content_nonce' );

	/* If footer content has been posted, run it through the do_shortcode() function. */
	if ( isset( $_POST['footer_content'] ) )
		echo do_shortcode( wp_kses_stripslashes( $_POST['footer_content'] ) );

	/* Always die() when handling Ajax. */
	die();
}

/**
 * Handles changing settings for the live preview of the theme.
 *
 * @since 1.4.0
 * @access private
 */
function hybrid_customize_preview_script() {

	/* Create a nonce for the Ajax. */
	$nonce = wp_create_nonce( 'hybrid_customize_footer_content_nonce' );

	?>
	<script type="text/javascript">
	wp.customize(
		'<?php echo hybrid_get_prefix(); ?>_theme_settings[footer_insert]',
		function( value ) {
			value.bind(
				function( to ) {
					jQuery.post( 
						'<?php echo admin_url( 'admin-ajax.php' ); ?>', 
						{ 
							action: 'hybrid_customize_footer_content',
							_ajax_nonce: '<?php echo $nonce; ?>',
							footer_content: to
						},
						function( response ) {
							jQuery( '.footer-content' ).html( response );
						}
					);
				}
			);
		}
	);
	</script>
	<?php
}

?>