JS compressor of world fame.Open work
Note that this is only tested with Chrome and Firefox. Should work with Safari as well, but most probably not with Opera or IE.
Paste your code in the left box. Click “GO!” to get compressed output on the right. The left-side will turn into the Ymacseditor. At this point if you click any token in the minified area, the editor on the left will move to the original location of that minified token.
Tick the “As I type”checkbox to turn on minification on-the-fly.
When the compressor warns, you'll get a flashing button in the toolbar. Click on it to display the warnings (temporarily covers the minified area). Click a warning in the list to go to that position in the source. If you have "on-the-fly" and fix warnings, the list will update automatically.
You can enable/disable the compressor, mangler and beautifier. For additional control check the buttons on the right ( “Compressor...”and “Codegen...”). Those options are saved in localStorage, they will be remembered the next time you visit this page.