#!/bin/sh

active_window="$(xdotool getwindowfocus)"
active_class=$(xprop -id "$active_window" WM_CLASS | awk '{print $4}')

if [ "$active_class" = '"firefox"' ]; then
    xdotool windowclose "$active_window"
else
    kill -15 "$(xdotool getwindowfocus getwindowpid)"
fi