Jquery.com provide 2 version of jquery library. I always use Minified version because i never edit anything in jquery base file. but what is the use and purpose of another Uncompressed Code version? Does people edit main library file to get something?
If yes then if we edit anything in main file then we can’t use google ajax library link.
Production (19KB, Minified and Gzipped)
Development (120KB, Uncompressed Code)
If you’re using the minified version during development, browsers will tell you there’s an error on line X, but line X might consist of hundreds or even thousands of lines of uncompressed code. This makes it very, very difficult to figure out what exactly caused the problem.
Developing against uncompressed code thus allows you to see what’s causing problems and fix. Minified jQuery should always be used in production, and the core functionality of jQuery shouldn’t be tweaked – that’s what plugins are for.
edit 5/2014: Source maps have been implemented in many browsers to allow debugging of minified code. https://developers.google.com/chrome-developer-tools/docs/javascript-debugging#source-maps