The default value for a variable that hasn't been declared is 'undefined'. But when using (if variable) {, the if will evaluate false for both the value "FALSE" and for "undefined", so the code works and has the variable at false first, but the variable probably should be declared first for readablitity, it's just lazier to do it that way.
As far as the second part of your question, I'll see if I can answer it later when I'm not so tired heh.