Unable to pass variable data

I am trying to use the following code to pass information to another site but it keeps giving me 开发者_StackOverflow社区an error:

Invalid Code:

$a = $b->doIt("James",$_SESSION['JNum'],"Frank"); 

Valid Sample Code:

$a = $b->doIt("James","123456","Frank");

In the first example, the page returns "number field is required". The second piece of sample code returns valid results. Do to the nature of this project though I need to pass the id number as they are stored in SESSION variables.

What am I missing?

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Did you start the session with:

session_start();

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you're missing $_SESSION['JNum']

var_dump($_SESSION['JNum']);

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Not only see if $_SESSION['JNum'] is set, using var_dump, but also make sure sessions are started at the top of yours script:

session_start();
var_dump($_SESSION['JNum']);