$ in id causes selector to fail

I'm trying to add some functionality to a existing application. I have no control over the input element ids. There are inputs I need to use that have $ in the id <input id='field1$0'>. Trying to use the id selector $('#field1$0') fails (result is undefined).

Is this a bug or "by design" in qQuery?

Is there a workaround, other than looping thru all inputs to find the ones I need?