Comment by lemonghost

It looks like the script is there to block phantomjs based bots (which can evaluate JS). It seems to check for the global properties mentioned in this article:

https://blog.shapesecurity.com/2015/01/22/detecting-phantomj...

If the properties are defined, it doesn't do anything, otherwise it reloads the page.

It is obfuscated but that seems to be what's going on anyway.