Why would I want to run a Webkit browser without a graphical user interface? Well there are a lot of good reasons actually. You want to search a page for something in an automated way. Or you may want to test a page from a script. Anyway, that is what PhantomJS allows you to do.
The story is a little old as I have been meaning to write this up for some time. However, the tool is pretty cool and worth a look.
From ReadWriteWeb: PhantomJS The Power of WebKit but Without the Broswer