For desktop browsers, use the Google CDN and your users probably won't download a thing. And for free, you get sane DOM interaction, and an enormous body of work papering over the differences between browsers.
And Google is one step closer to tracking everything everyone does on every website.
As if now forcing people to deploy Google Analytics on their websites if they want keyword data from Google wasn't enough, do we really want to help and encourage Google to get in a position where they effectively control the entire internet?
One company controls over 90% of internet search and referral and they actually have the power to kill any company they don't like. Right now they may be behaving, but what if some competitor comes along which is showing some edge? Can we trust Google to do the right thing?
Google also hosts files needed by a majority of websites. They also withhold information from you about you and your site and force you to register an account with them and deploy their software on your sites to get access to a subset of that information. And you are encouraging people to help that company get a stronger grip. For what benefit? At what cost? Sorry for not being a fanboy, but try looking at the bigger picture here.
Would you be OK with one company controlling the entire Internet if that company was Apple? If it was Microsoft?
Hosting your own 23kb jQuery file does not cost that much. Actually practically nothing. Not in terms of bandwidth and neither in terms of perceived performance. Unless you are hosting your website on a 36.6kbps modem, host your own. Do the web some good.
As long as you link the right files (make sure you specify the specific version and not use the one to give the lastest), there are very long expires headers and Google will have no idea the vast majority of your users ever visited. A user just needs to visit one site using the same version of Google hosted jQuery and they won't have to download it again when visiting another site.
> Hosting your own 23kb jQuery file does not cost that much. Actually practically nothing. Not in terms of bandwidth and neither in terms of perceived performance. Unless you are hosting your website on a 36.6kbps modem, host your own. Do the web some good.
People aren't using Google CDN for the cost, but for the performance. A high percentage of user will have the file cached already, so the performance gain is quite significant. Doubly so in a mobile environment.
Also some places like Apple have their own internal js frameworks and want folks who know and can code bare-metal js.