LayerSlider – Uncaught ReferenceError: jQuery is not defined

Hey Mike,
Thanks for your reply.
Regarding Raidboxes: This is my hoster. They also block specific files so one cannot mess up their site. However, the hoster was never the problem so far and there were no significant changes in the past few weeks. The “purge cache” should … well … purge the cache :D but you’d need to refresh with the link. Apparently it only sets the addition to the link, nothing else.

I deactivated all plugins (in staging mode) and nothing changed – so it’s not any plugin.

Anyway thanks for the hint with the child theme. This was the main problem.
I added this code to the functions.php – I think for PageSpeed reasons:

// Defer Javascripts
// Defer jQuery Parsing using the HTML5 defer property
if (!(is_admin() )) {
    function defer_parsing_of_js ( $url ) {
        if ( FALSE === strpos( $url, '.js' ) ) return $url;
        if ( strpos( $url, 'jquery.js' ) ) return $url;
        // return "$url' defer ";
        return "$url' defer onload='";
    }
    add_filter( 'clean_url', 'defer_parsing_of_js', 11, 1 );
}

Do you have any idea why this problem just occured this week and never before? It doesn’t really make sense to me … 

Thanks you very much!

Cheers
Patrick

But then again – how would this happen if I turn any plugins off? It seems logical to me that by turning all plugins off there shouldn’t be any problems!?