New Post: Understanding: Client side and grabbing information

Okay so, 

In my lets call it 'index.php' file it contains:

The message information saying 'please download file here' with the excecutable button to 'PHPExcel.php'

Index.php contains:

var x = new Date();
TheToken = 'ExportXYZ' + x.getTime ();
document.getElementById('TokenField').value = TheToken;

this piece of code, Is the 'tokenfield' the div on index.php which will show the token information?

PHPExcel.php contains:

If(array_key_exists('Token', $_POST) && $_POST['Token']!=") setcookie($_POST['Token'],'Ready');

When I put this into my PHP I have a syntax error here: 

array_key_exists('Token', $_POST) && $_POST['Token']!=")

I tried to do some revision into setcookie from php.net but still can't understand it. Is this the information that makes the token, or is it the javascript makes the token?