I have quite a few of these in Apache logs piling up every day:
[Mon Jun 09 20:42:58 2014] [error] [client 188.8.131.52] File does not exist: /home/user/public_html/ajax.googleapis.com, referer: http://www.mysite.com//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js
I have over 200k visitors per day but a few of them like a dozen or so are generating the above error. I can't figure out what may be causing it. Checked the html code and it's all good so I ran out of ideas.