/**
  * @return ContrexxJavascript Singleton instance
  */
 public static function getInstance()
 {
     if (null == self::$instance) {
         self::$instance = new self();
     }
     return self::$instance;
 }
 /**
  * @return \ContrexxJavascript Singleton instance
  */
 public static function getInstance()
 {
     if (is_null(self::$instance)) {
         self::$instance = new self();
     }
     return self::$instance;
 }