checking a value in RJS

Basically I want to toggle the value of an element on a page via RJS. I can set the value fine, but I simply cannot figure out how to check the current value. This is essentially what I want to do:

if page["element_id"].value == "0"   page["element_id"].value = "1" else   page["element_id"].value = "0" end

The assignment lines (e.g. page["element_id"].value = "1") work fine. It's that line to check the current value of the element that is killing me.

Any experience with this?

(Note: I have the RJS Templates for Rails PDF "book", but there is no mention of detecting or assigning values. And as usual, there isn't much else out there on the 'Net.)

Thanks. I was thinking about your suggestion, but I did not wish to go on a wild goose chase and I couldn't find any confirmation for the idea out on the 'Net. Anyway, it looks like the above pretty much solves the problem.