[man]file_get_contents/man of a local file....
Use the above to get the contents (HTML, PHP, Text, XML, etc.) and put that as the default contents of the text-area. Then, on submit, grab that content, and use:
$fp = [man]fopen/man;
top open a file pointer, then use
[man]fwrite[/man]($fp, $_POST['contents']);
to write to the file. Then just close it:
[man]fclose/man;
Hope that helps.
