add_filter('shutdown','somefunction',0);
function somefunction() {
 if(!is_admin()){
  global $something'
  if($something['switch-on'] == '1') {
   if($something['multipanel-on'] == '0' && $something['menu-on'] == '0'){
    $insert .=  '<div id="div1">something here</div>';
   }
   if($something['multipanel-on'] == '1') {
    $insert .=  '<div id="div2">';
    $insert .= '<ul class="carousel_buttons">';
    $insert .= '<li><a href="#" id="carousel_prev"></a></li>';
    $insert .= '<li><a href="#" id="carousel_next"></a></li>';
    $insert .= '</ul>';
    $insert .= '</div>';
   }
   if($something['menu-on'] == '1') {
    $insert .= '<div id="div3">';
    $insert .= '<ul class="panel_list">';
      $insert .= '<li>';
       $insert .= '<a href="' . $url . '">';
        $insert .= '<i '.$class1.'></i>';
        $insert .= $menupost->post_title;
       $insert .= '</a>';
      $insert .= '</li>';
    $insert .= '</ul>';
    $insert .= '</div>';
   }
   $content = ob_get_clean();
   $content .= preg_replace('#<body([^>]*)>#i',"<body$1>{$insert}",$content);
   echo $content;
  }
 }
}