// Skeleton from https://gist.github.com/392765
class WidgetWithBehaviorScript extends WP_Widget {
 
function __construct() {
parent::__construct(__CLASS__, 'Widget with Accompanying Behavior Script', array(
'classname' => __CLASS__,
'description' => "This WordPress widget serves as a pattern for how to enqueue a script only if the widget is actually rendered."
));
 
// Enqueue the .js script which accompanies the widget
wp_enqueue_script(
__CLASS__,
trailingslashit(get_template_directory_uri()) . __CLASS__ . ".js",
array('jquery'), // Whatever you want
filemtime(trailingslashit(TEMPLATEPATH) . __CLASS__ . '.js'),
true // Must be true (in_footer)
);
 
// Schedule an action to remove the enqueued script; this action is
// removed if the widget is actually rendered (if the widget() is called)
add_action("wp_print_footer_scripts", array(__CLASS__, 'remove_enqueued_script'));
}
 
/**
* Remove the enqueued script
*/
function remove_enqueued_script(){
wp_deregister_script(__CLASS__);
}
 
function widget($args, $instance) {
// Abort the scheduled removal of the enqueued script because the widget is being rendered
remove_action("wp_print_footer_scripts", array(__CLASS__, 'remove_enqueued_script'));
 
extract($args, EXTR_SKIP);
global $Shopp;
 
echo $before_widget;
echo $before_title;
# ...
echo $after_title;
# ...
echo $after_widget;
}
 
function update($new_instance, $old_instance) {}
function form($instance){}
}