> Or is it something to do with hosting your own copies of the libraries instead of a CDN (I thought this was frowned upon)
I rarely use CDN copies of scripts for work projects. When Google first set up their CDN for jQuery, I used it on a client's custom e-commerce system. Client called us up and SCREAMED at our development manager because he was getting a warning that the admin section of his brand new site was insecure.
Google was using an invalid SSL cert for the CDN's domain. It was completely out of our control. But that's the problem -- what gets served up is completely out of your control. It could have a bad/missing SSL cert. The file could go missing. Or it could be replaced with malware. It's not worth the couple milliseconds you're going to save.
I rarely use CDN copies of scripts for work projects. When Google first set up their CDN for jQuery, I used it on a client's custom e-commerce system. Client called us up and SCREAMED at our development manager because he was getting a warning that the admin section of his brand new site was insecure.
Google was using an invalid SSL cert for the CDN's domain. It was completely out of our control. But that's the problem -- what gets served up is completely out of your control. It could have a bad/missing SSL cert. The file could go missing. Or it could be replaced with malware. It's not worth the couple milliseconds you're going to save.