Back in post 28, I described my method for getting data from my Pi to its web page. That's been working for a few weeks now.
A few days back I added a FORM SUBMIT button that can control how the Pi operates. The new feature is at the bottom of http://raspi-online.info/. The button is labeled "LED On!".
When that button is clicked PHP code in that page writes a particular value into a data file on that server.
Once per minute the Pi reads that same file -- like so:
a=`curl --silent --netrc -R ftp://ftp.???.com/data/led`
if [ "$a" = 'ON' ] ;
curl --silent --netrc -T web/null ftp://ftp.???.com/data/led
sudo python web/flashled.py