code: public void setUrl(String url) {
          this.url = url;
  
          if (child != null) {
              child.destroy();
              child = null;
          }
  
          if (url.startsWith("http") || !url.endsWith(".fsp")) {
              child = new Iframe();
              ((Iframe) child).setSrc(url);
          } else {
              child = new Import();
              ((Import) child).setSrc(url);
          }
  
          fullSize(child);
          root.addChild(child);
      }
docs: Sets the URL of the content to be retrieved. If the URL starts with "http", it is fetched
  into an iframe. Otherwise, an include component is created and used to fetch the content.
  
  @param url Content URL.