/**
  * Generate any HTML that needs to go at the start of the <body> tag.
  *
  * Normally, this method is called automatically by the code that prints the
  * <head> tag. You should not normally need to call it in your own code.
  *
  * @param renderer_base $renderer
  * @return string the HTML code to go at the start of the <body> tag.
  */
 public function get_top_of_body_code(renderer_base $renderer)
 {
     // First the skip links.
     $output = $renderer->render_skip_links($this->skiplinks);
     // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
     $output .= $this->get_yui3lib_headcode();
     // Add hacked jQuery support, it is not intended for standard Moodle distribution!
     $output .= $this->get_jquery_headcode();
     // Link our main JS file, all core stuff should be there.
     $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
     // All the other linked things from HEAD - there should be as few as possible.
     if ($this->jsincludes['head']) {
         foreach ($this->jsincludes['head'] as $url) {
             $output .= html_writer::script('', $url);
         }
     }
     // Then the clever trick for hiding of things not needed when JS works.
     $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
     $this->topofbodydone = true;
     return $output;
 }