Admin interface javascript errors

There appears to be several problems with the javascript on the edit discounts admin page, as reported:

http://drupal.org/node/540080#comment-2917106
http://drupal.org/node/783952

To put it simply, the textareas that are supposed to slide up/down do not work (they always stay hidden). This is being caused by a javascript syntax error.
It's a bit of a strange one because they were fine for me a couple of months ago. I've been through all of the recent revisions and can't find any changes made.

That said, the implementation of the javascript was not the best anyway. Creating hidden form elements just so that a wrapped div could be inserted and placing all the code into the onclick attribute.

So I've created a patch that attempts to solve both issues with all the js inserted using drupal_add_js() (I've also amended the product/terms/skus filter so that all the js is kept in one place).

I have yet to test this on all browsers, so let me know if anyone comes across any problems.