I am assuming you want to log http access to any site through your router perhaps for traffic analysis.
You can do so by the below, but do note that it would be very verbose and file will be large over time.
You would need to enable custom scripts through your administration UI if you have not done so as of now.
Login in to your router through telnet/ssh and
go to
cd /jff/configs
I would suggest you create a USB folder to contain the logs for traffic as the file will be very large.
If you do not want to store it in the file you can keep the comment as it is.
Create or add to file dnsmasq.conf.add
#Logging
#log-facility=/tmp/mnt/YOURUSBMOUNTEDDRIVE/FOLDERTOHOLDLOGFILE/dnsmasq.log
log-queries