It happens when I use some Guest internets(Tried the guest Wifi in stanford university & emory university). And sometimes it just happens even I'm in the office, and it will be fine again in like 10 minutes. It only happens to some computers as well in the office(All MAC OSX w/ safari) and some of them are fine. To be it's like totally random unless I'm under some guest wifi.
What could be the reasons?
Edit: I noticed that on some circumstances, I have functions defined after the place they are called. Could this be the reason?
You need to use a Jquery CDN that supports https, or put the code on your own site/server and include it from your domain. Here are two examples which will work over ssl.
I generally trust google libraries as a cdn, its up to you.
If you don't want to trust google you can deploy it on your own.