Creating a Preview for a form, like google adwords

So I am making a simple form form customers to fill out, and I want users to get a preview of what their submission will look like. A great example of this is google adwords, when you are creating a new ad.

Basically this has to be done through ajax, updating the preview div depending on what the user has entered into the form fields. I figured I could do an onChange function that updates the div, but I believe that only works when the user finishes with that field and moves on to another one,开发者_开发问答 which is fine, but it would be nice if it could happen in real time, as the user types in that field.

What should I look into to go about doing this?

It may or may not having some bearing, but I am using Rails 3.

Thanks!

---

Even if you're not using jQuery, this will help to understand onChange: http://api.jquery.com/change/

Your approach with having a preview div sounds ok. Inside this div you can map other divs (or any tags) to each input.