Could anyone answer my few questions below?

1. Why on the <a href=$cgi_url?work=admsearch&user=$user> What does that question mark refers to? I don't see any codes that associated with that, i meant cgi.

2. On the submit action form, the code is like this <td width="100%"><form enctype="multipart/form-data" method="POST" action="$cgi_url?user=$user">
Again why not form.cgi or something instead $cgi_url?user=$user. I really completely lost about this code.

Please and please, i really cannot find sources info on the web.