ok, you used to be able to use a variable immediately if it was supplied to the script via POST, GET, COOKIE, or SESSION.
Now, with the default settings in PHP you must tell the script how the value was submitted.
Most forms use POST so you would use $POST["variablename"] to get the value. If you need to be able to get the value from POST and GET or any other combination then you need to use $REQUEST["variablename"].
It's a matter of security. What if you wrote a shopping script and my total was passed from page to page using a hidden form element. Then I figured this out and put a ?total=0 on the url line on the next page. PHP would have two variables called total and would choose one over the other. If it chose my 0, then I get my purchase for free!
The Register Globals off ensures that I can't do that, because you are telling PHP to only get the total value from the $_POST. The value that I passed through the URL would simply be thrown away.
Again, it's really only a matter of security. If security is not a big deal, go ahead and turn Register Globals back on, but if you upgrade to a newer version of PHP in the future, you are going to have to remember to go back into your php.ini file each time and turn Register Globals back on since the PHP group will only endorse the newer method.
In order to keep from having to turn Register Globals on each time you upgrade PHP, you could just write your code with nothing but $_REQUEST to access the variables. Then it doesn't matter how the value was passed to the script. It will always retrieve it.
