I just started using googleapis.com where they host jquery codes for use. I am using:
https://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js
Now my question is if these codes are always there? or are they ever removed because i plan to use the source of the script as the one above.
They’re always there, and you should consider using version 1.7.2 as of right now!
Millions of websites get the jQuery files from the Google API, so there’s not a huge risk of them being removed any time soon, unless they are really outdated.