pt from
// http://www.thesitewizard.com/javascripts/change-style-sheets.shtml
  var i, link_tag ;
  for (i = 0, link_tag = document.getElementsByTagName("link") ;
    i < link_tag.length ; i++ ) {
    if ((link_tag[i].rel.indexOf( "stylesheet" ) != -1) &&
      link_tag[i].title) {
      link_tag[i].disabled = true ;
      if (link_tag[i].title == css_title) {
        link_tag[i].disabled = false ;
      }
    }
    set_cookie( style_cookie_name, css_title,
      style_cookie_duration );
  }
}
function set_