Packer (p,a,c,k,e,r) is a system which is quite common for obtaining lightweight and incomprehensible javascript files.
It uses several algorithms to reduce the file size and confuse things; Amongst these, only few can be undone
Things that can be restored
function names
function code
Things which cannot be undone:
Names of the parameters of a function
Comments (those are removed totally)
So let's get to your code: paste the whole thing below; it should look something like:
eval(function(p,a,c,k,e,d){...}))
(opens in new window)
Note: a new tool is now available which also formats code in a nice way, so go away to jsbeautifier