When editing a javascript file eclim will default to validating the file when it is written. Any errors will be added to the current window’s location list (:help location-list) and their corresponding line number noted via Vim’s sign functionality.
Javascript validation currently uses JavaScript Lint to perform the validation. To use it you will need to first install JavaScript Lint and put it in your path.
Installing on windows and the mac should be very straight forward since pre-compiled version for each are available for download on the JavaScript Lint site. For other unix based systems (linux, bsd, etc.) the installation procedure is not so obvious. Here are the steps used to compile and install it on a linux machine (your paths may vary):
$ cd jsl-<version>/src
$ make -f Makefile.ref
# this path will undoubtedly vary on non-linux machines, so watch the
# make output for the real destination.
$ sudo cp Linux_All_DBG.OBJ/jsl /usr/local/bin
If you don’t want javascript files validated when saving them, you can set the g:EclimJavascriptValidate variable described in the configuration section below.
Regardless of whether you have validation enabled upon saving or not, the command :Validate is available to manually execute the validation.