Thank you all for your help. Mostly with James Keeline's reply but
also with O'Reilly's PHP Cookbook I was able to suss out a workable
solution.
Just so that anyone else who is dealing with a similar problem,
especially for those dealing with Dreamweaver-generated content, what
I ended up doing was replacing the line
GetSQLValueString($_POST['category'], "text"));
with
GetSQLValueString(join(',',$category), "text"));
A note on José Guilherme H. Arantes' suggestion that I use "ENUM" as
my MySQL datatype for the category field in my database: ENUM is to be
used when there are several possible values but only one will be
entered. If there are several possible entries and none, any or all
values may be entered the datatype should be SET. At least that's how
I understand it, but my knowledge of MySQL is minimal.
David
