If you developing rich web applications, you start to think how to compress JavaScript to keep bandwidth and page load times as small as possible. I found 5 different tools to compress javascript files, which can be run using cron, or run on some event to automate work on production-server.
1. JSMin. Commonly used compressor, based on simple rules, ported on many languages, including JavaScript
2. JavaScript::Minifier. Separate perl module, compression ratio equal to JSMin
3.Dojo ShrinkSafe aka Rhino. JavaScript compressor that parses the JavaScript using the rhino library, included in Dojo. Run as jar-module.
4. Dean Edwards Packer. Well-known tools from far-famed Dean Edwards. Ported on some languages, including PHP4/5.
5. YUI. JavaScript minifier designed to be 100% safe and yield a high compression ratio. Run as jar-module.
From my own experience i can tell
– no sense to compress files less 1 kb
– packer shows best results ( just my own opinion )
– always check you functionality of your compressed files. You can try to verify your code with JSLint
– remember that you can gzip compressed files to get smaller file