Compressing your minified JS and CSS takes another great step. Compressing is a very common technique these days and it could be said that it’s been almost completely mastered by the community. Basically, compression takes patterns of code and rewrites them in a simpler form based on number of occurrence. Example: in a file, reading patterns such as “OOOOOOOO” (simple example), why not create a code such as “O*8″ and for any * sign, use a \*. This takes your 8 characters down to 3. A basic principal for compressing code. And as you can see above with jQuery, taking development code of 223KB down to 31KB makes it an easy decision. Imagine if you are hosting a jQuery server where everybody is pulling from your source. If you can decrease your files by 7 times, you’ll only need 1 server for the 7 you may have needed before.
Combining your scripts also increases your websites performance. The more files that you have, with several JS, CSS, and Image files, the longer it’s going to take to get all of your data. For each file, you require a new HTTP request. And for each HTTP request, you begin a new TCP/IP transaction which requires going through testing bandwidth over and over. If you combine your files into one JS, CSS, or Image file, you can cut down the number of streams and download quicker with a well established TCP/IP connection. JS and CSS files are easy to combine because they are just text. But you can also combine images using CSS sprites.
These are very common performance tips for running and maintaining your web servers and websites. Take a look at Yahoo’s best practice guide: