Enhance required input field

There are tons of articles out there about forms, particularly forms on eCommerce sites.
I’ve been to a lot of sites that have bad forms. The form on my contact page isn’t great itself, but I’m working on it.

I saw something particularly interesting today though. A form that focuses in on the required fields. So if for example you miss a required field in the process of filling in a form, the required fields are brought into focus for easy completion. A screenshot is below…

Screen Shot 2013-05-14 at 12.13.06 AM
View the demo

Would be good to see something like this as progressive enhancement on an eCommerce site, and to measure if implementing a solution like this aided to decrease the number of abandoned carts in the checkout process.