XF 2.1 xenforo syntax HTTP REFERRER

[fred66]

Is there a way to check whether a user came from a thread?
like HTTP REFERRER from /threads/
I've already looked at $xf.request, but can't find any documentation about it

 

[Kirby]

$xf.request.getServer('HTTP_REFERRER')

 

[fred66]

thank u!!
from where do u know the syntax?
output is always false

 

[fred66]

$xf.request.getServer('HTTP_REFERER')
works