I am not sure what the proper terminology is, but how can a web app know what platform the guest is using to view/use the app? For example a guest using Win7 is likely to have one size screen, as compared to a guest using iOS on a iPhone or yet another using iOS on an iPad will have two different size screens. The application should auto adjust to a best fit, or even serve a different form that has a different layout.
Not sure how to know what the user has, and also best practice to provide a screen/form that will work best for their viewing. Can anyone suggest some ideas?