Check box validation on .pl form

[Princessjo]

I'm trying to use the basic formmail script (freebie from hosting company) and everything seems to be working fine but I need to validate that the user checked the check box which says they have read and understood the terms and conditions. I have a javascript snippet of code which worked on my old asp coded form (someone else developed) but now that I've moved to a Linux/PHP environment it's not working. I'm new to this stuff as you can tell.....

Does anyone know how to do a validation on a checkbox?

[DrDoc]

Let's say the name of the checkbox is "foobar"...
If the box was checked, then you can extract $foobar as a variable...
If the box wasn't checked, you won't be able to...

It's that simple ;)

[Princessjo]

how do you extract $foobar as a variable?

[DrDoc]

How do you currently parse the POST/GET query string?

[Princessjo]

Here is my query string

<FORM METHOD=POST ACTION="http://mydomain name.com/cgi-bin/formmail/FormMail.pl">
<input type=hidden name="recipient" value="[e-mail]">
<input type=hidden name="subject" value="Booking form">