hide 856$u PDFs in Koha if users aren't logged in

hide-pdf-urls.js

// run 1) on opac-detail pages & 2) if no user is signed in
if (!!location.pathname.match('/cgi-bin/koha/opac-detail.pl') && !$('.loggedinusername').length) {
    // replace 856$u links with a link to login instead
    // this would need to be tweaked if there are multiple URLs per record
    $('.results_summary.online_resources a')
        .replaceWith('<a href="/cgi-bin/koha/opac-user.pl">login to view PDF</a>')
}