[jQuery] Firing function on any form element changing?

[mo2g]

I have a script that fires if any input or select element changes on
my form:

        $('input, textarea, select').change(function(){

First, is this the correct way to do this?

Second, how do I make sure that only the elements in form "myform" are
the one that are being monitored for change? The form appears on a web
page with other forms.

I tried:

        $('input, textarea, select', myform).change(function(){

but it says that myform is undefined.