One of the most prevalent uses of javascript insertion is automatic re-directs. For example, the user opens an invoice that is overdue and instead of seeing the invoice, they are redirected to a page in the collections department. Another typical application if record types: if the record type is strategic project, open one form; if it is a short term project, open a different form. (Form rules can only take you so far - when the forms are totally different, with different tabs and sections, form rules are not sufficient.)
I wish there was some way to create this capability without script insertion.
