how to read not submitted field value

how to read not submitted field value

Hi all,
I am very new to JQuery. In fact this is my very first project where I am trying to use it.
I have a page built in ColdFusion where I have a text field in which user will enter a code (B12, for instanse). I am trying to make a lookup page using the value of this field. I am planning on passing the value of the field to the page where this value will be passed into a d/b query. User will not hit a button to send this page to the server yet. Is it possible to do it via JQ?

Thanks,
Eugene