I've always shied away from this and used the full path but how is it correctly done?

I have a directory with this path: http://localhost/JQuery/JQueryHello.html
and in this file i want to point to this: http://localhost/jquery/JQuery-HW/jquery-1.9.1.min.js

so do I put <script src=”/jquery-1.4.2.min.js” type=”text/javascript”></script>

or

<script src=”JQuery-HW/jquery-1.4.2.min.js” type=”text/javascript”></script>

or what exactly?