how to include .js file into javascript file

we can include javascript file into html file
for example
<script src="../classes/dynCalendar.js" type="text/javascript" language="javascript"></script>

but i want to add (../classes/dynCalendar.js) into javascript file.

You can search this forum to get previously answered questions.
I did and found this (http://www.codingforums.com/showthread.php?t=64488#post337558).