just starting PHP and WML

[x2srj]

Hi,

I've got a wml page that passes a variable:

<go href="bookingref_truncate.php?bookref=MU4657">

this goes to a PHP page like....

<card id="booking">
<onevent type="ontimer">
<go href="search.wml#step1">
<?php

$changeBookref = substr('bookref', 0, 2);

if ($changeBookref == "AB"){
echo "<setvar name=\"bookref\" value=\"ABBA\" />";
}
else ($changeBookref == "MU"){
echo "<setvar name=\"bookref\" value=\"MUSE\" />";
}

blah blah blah blah blah blah

This PHP page I need to do two things; one I need to truncate the value to just the first two alphanumerics; and secondly I need the if statement to pick up the value and pass it correctly... The trouble I'm having is I don't appear to be getting the value???

help PLEASE :))))))

Many many thanks in advance :)