Modify $_POST

[Shoshana]

Hello folks,
Ive seen lots of recommendations to not try to do what Im trying to do
but let me put it this way and hopefully someone can tell if this is a
good idea or not (or an alternative).

What Im trying to do is this. I have a series of links that when
clicked will navigate to a common page passing in a value encoded in
the link. For reasons not worth going into I cant use a querystring.

I was hoping to call a javascript function from the onclick event of
the link, then assign a new $_POST variable and then submit the form
(hence enabling me to read the $_POST value from the receiving page.

Im aware that I could do the same thing with a $_SESSION but as this is
the last stage of this app and I havent had to use sessions yet I was
hoping to avoid it (for no real reason admittedly - I just got
interested in the solution above as an idea).

I hope this is clear.