Using a .js in a .js

Hi,

I am trying to use the lightwindow script inside my unblockable popup window script. Apparently, it doesn't work. How do I put a .js inside a .js? Simply listing them in my head tags doesn't seem to work

eg.

<script type="text/javascript" src="javascript/prototype.js"></script>
<script type="text/javascript" src="javascript/effects.js"></script>
<script type="text/javascript" src="javascript/lightwindow.js"></script>

<script src="dw_lib.js" type="text/javascript"></script>
<script src="dw_glider.js" type="text/javascript"></script>
<script src="CounterHandler.js" type="text/javascript"></script>

Any tips?

Thank you,
Donny