Live Search / auto_complete + HABTM = possible?

I am attempting to add in a form field that should allow me to add a record into a join table. The table name contains the ids of the following:

log_id node_id

So naturally, my models is setup as follows:

class Log
  has_and_belongs_to_many :nodes
end

class Node
  has_and_belongs_to_many :nodes
end

The objective is that when I create a log, I should be able to associate it with an number of nodes (ergo, servers). And since there is a lot of nodes on hand, it seems to make sense to have a textfield where when you enter a node name, it will pop-up a list of nodes to choose from. However, I 开发者_StackOverflow社区am having some difficulty getting that accomplished.

I know how to use the autocomplete plugin, (that had came with Rails), but it seems to only accept a string and not with the id - and apparently not across models. I know how to do an AJAX search (though I am not that familiar with Javascript), but again, getting that ID becomes an issue.

I think that in either case, I may be able to figure how to get that value and put that in - the uncertainty is whether one or the other is the correct approach to getting that value. Which one should I concentrate on? Or is HABTM even appropriate in this?