My program currently has a "Save" button, which saves the latest version of the
data. However I soon realised that it was all too easy to overlook this step
before moving on to something else, and started thinking about the best backup
strategy. I don't like the Word strategy of trying to catch shutdown commands
and putting up a "Want to save this" screen, and now think the best strategy
would be to make a dated backup file when the program was opened (and perhaps
every hour or so thereafter), and then to save every change back to disk as soon
as it was made.

At the moment I think I could afford to save the changes before I load the next
page, but if my database gets much bigger this might take a significant time, so
that it would be better to do it after the page was loaded. This brings up the
dual questions of when the HTML page becomes active, and when the php stops
running. Every page I have ever seen which uses php ends with the lines:

?>
</body>
</html>

Is it possible to run a save procedure after the </html> or would any php after
this command not be executed? And if I put a save procedure taking a few
seconds before the </body> line, would the page respond to the user immediately,
or not until the save procedure had finished?

It sounds as if the exec command might offer a better solution, but the manual
does not make it clear whether this can execute a user-defined command, or only
a system command.


Clancy