function bookmark()
{
    bookmarkurl = "http://www.londonair.org.uk";
    bookmarktitle = "The London Air Quality Network";
    if (document.all)
        window.external.AddFavorite(bookmarkurl,bookmarktitle)
    else if (window.sidebar) // firefox
    window.sidebar.addPanel(bookmarktitle, bookmarkurl, "");
}