saving changed data
input type hidden fields and write the data changed to it, or form text fields
that receive user data (if that is what you are doing). Then at some point the
form has to be submitted. Saving the data is actually a server side process.
You can use ajax or have the page submit to itself and use php in the page
to look for GET of POST vars and do what is necessary on the server side.
Data bases can be used if available, or create flat file (plain text) files that
I use php on the server side. But this off topic for this forum section as I can