[PHP] window.open (javascript)

[Eduardo Kokubo]

I passed some vars to another page using window.open and it worked fine (but had to 
hide the toolbar). The problem is that wen I check their values like this:
<?php
if ($test){
  print "<b>Test: </b>";
  print $test;
  print "<br><br>\n";}

if ($adicionais){
  print "<b>Informações adicionais: </b>";
  print $adicionais;
  print "<br><br>\n";}

?>
This code always prints Teste and a "0" when it shouldn't print anything. 

<?php
if ($test != 0){
  print "<b>Test: </b>";
  print $test;
  print "<br><br>\n";}

if ($adicionais != 0){
  print "<b>Informações adicionais: </b>";
  print $adicionais;
  print "<br><br>\n";}
 
?>

This one never prints anything. When I use " " or ' ' to check the 0, it happens the 
same thing that the first code.
The other vars that don't use if are working fine. Can anybody please explain this?