If you have a site which is running on SSL and used content that make non-https request then you need to a bit worried.
The default setting of Firefox 23 will block the content that called on non-https address and page is based on SSL.
script using https://code.jquery.com/jquery-1.10.2.min.js will not work because code.jquery.com can not be reach on https.
the cdn ajax.googleapis.com support SSL so you can try it.
if you want to disable this settings you can modify it on about:config
change the value true to false and it will be disable (it’s just for example)