Menambahkan Custom Class ke Widget

add-to-functions.php

/*** Menambahkan Custom Class ke Widget ***/

function lmd_widget_form_extend( $instance, $widget ) {

	$row = '';
	
	if ( !isset($instance['classes']) )

		$instance['classes'] = null;

		$row .= "<p>Class:\t<input type='text' name='widget-{$widget->id_base}[{$widget->number}][classes]' id='widget-{$widget->id_base}-{$widget->number}-classes' class='widefat' value='{$instance['classes']}'/>\n";
		$row .= "</p>\n";

		echo $row;

	return $instance;
}
add_filter('widget_form_callback', 'lmd_widget_form_extend', 10, 2);
function lmd_widget_update( $instance, $new_instance ) {
	$instance['classes'] = $new_instance['classes'];
return $instance;
}
add_filter( 'widget_update_callback', 'lmd_widget_update', 10, 2 );
function lmd_dynamic_sidebar_params( $params ) {
	global $wp_registered_widgets;
	$widget_id    = $params[0]['widget_id'];
	$widget_obj    = $wp_registered_widgets[$widget_id];
	$widget_opt    = get_option($widget_obj['callback'][0]->option_name);
	$widget_num    = $widget_obj['params'][0]['number'];

	if ( isset($widget_opt[$widget_num]['classes']) && !empty($widget_opt[$widget_num]['classes']) )
		$params[0]['before_widget'] = preg_replace( '/class="/', "class=\"{$widget_opt[$widget_num]['classes']} ", $params[0]['before_widget'], 1 );
	return $params;
}
add_filter( 'dynamic_sidebar_params', 'lmd_dynamic_sidebar_params' );

Origin: https://gist.github.com/CEscorcio/5669905