code: public function renderAjax($view, $params = [], $context = null)
      {
          $viewFile = $this->findViewFile($view, $context);
  
          ob_start();
          ob_implicit_flush(false);
  
          $this->beginPage();
          $this->head();
          $this->beginBody();
          echo $this->renderFile($viewFile, $params, $context);
          $this->endBody();
          $this->endPage(true);
  
          return ob_get_clean();
      }
docs: Renders a view in response to an AJAX request.
  
  This method is similar to [[render()]] except that it will surround the view being rendered
  with the calls of [[beginPage()]], [[head()]], [[beginBody()]], [[endBody()]] and [[endPage()]].
  By doing so, the method is able to inject into the rendering result with JS/CSS scripts and files
  that are registered with the view.
  
  @param string $view the view name. Please refer to [[render()]] on how to specify this parameter.
  @param array $params the parameters (name-value pairs) that will be extracted and made available in the view file.
  @param object $context the context that the view should use for rendering the view. If null,
  existing [[context]] will be used.
  @return string the rendering result
  @see render()