Script to send a F5 key press to the foreground app, if this is Chromium it will refresh the page.
NOTE: It may be necessary to send an Alt Tab key press to bring the desired app or app window to foreground.
Create a script:
sudo vi /opt/scripts/chromium-refresh.sh
#!/bin/bash
export DISPLAY=:0.0
export XAUTHORITY=/home/pi/.Xauthority
/usr/bin/xdotool key F5
Update the permissions
sudo chown pi.pi /opt/scripts/chromium-refresh.sh
sudo chmod u+x /opt/scripts/chromium-refresh.sh
sudo chmod +x /opt/scripts/chromium-refresh.sh
Test:
/opt/scripts/chromium-refresh.sh