Custom javascript file upload for form field validation

Hi, 

I'm preparing multiple complex custom forms having more than 15 custom fields and they required a interrelated validation between each other (also some functions can be reused like date validation and all). The possible way out to work on those complex validation is using java script block.But that have following limitations -

1. You can't write more than 500 characters in that field (restricting you not to create complex logic)

2. You can't reuse any function which can be reused by other form.

Now can I create a js file with all the custom java script methods and upload in Aveksa and access those js functions from any form possibly by mentioning validation URI ?

Any clue will be appreciated. 

Thanks, Amit