Echo html in <head> with jquery?

Echo html in <head> with jquery?


Hello,
I am almost certain one of you guys will have a super quick solution
to this, but I just can't get it and it is doing my head in:
I have this piece of code which basically checks on client-side what
time of the day it is.
This information should be used to "use" different stylesheets based
on the time, e.g.