tools that are recommended to be used along with it are:
-Closure Inspector Add-On for firefox.
there are two ways using the Closure Compiler through command-line, and the online service,
first one, is by using the recent build, that can be download from this URL: http://closure-compiler.googlecode.com/files/compiler-latest.zip.
to use the advance attribute of the compiler you might want to use the following command:
second way is using the online service at http://closure-compiler.appspot.com/home