See Absolute, document-relative and site root-relative paths:
http://help.adobe.com/en_US/dreamweaver/cs/using/WScbb6b82af5544594822 510a94ae8d65-7c44a.html
If you use DW to insert scripts into documents, it will create the correct path for you.
Go to Insert > Script > Script > browse to folder, choose script, hit OK.
Nancy O.