include v JS

Lze udelat include file v JS nejak jinak nez takto?
<script type="text/javascript" language="javascript" src="levels.js"></script>

Chtel bych to pro vice souboru a predstavoval bych si asi neco takoveho:
<script type="text/javascript" language="javascript"><!-- Begin
include="levels.js"
include="levelsaaa.js"
include="levelsbbb.js"

var... function... normalni pokracovani scriptu
// End --></script>