Because of weird charging behavior of my 40.- CHF flea market laptop with chinese knock off battery, I was in need of a battery monitor.
# m h dom mon dow command
*/5 * * * * date -Iseconds | cat /dev/stdin /sys/class/power_supply/BAT0/uevent >> /home/marco/repos/batterMon/batter_log.txt && python /home/marco/repos/batterMon/batParse.py /home/marco/repos/batterMon/batter_log.txt > /home/marco/repos/batterMon/data.csv
No need for a local webserver. Just use 'file:///-urls.
firefox file:///home/marco/repos/batterMon/index.html