CSS class of Form elements

Question

I'm trying to get all the information of my WFFM Forms in sitecore 7. I could retrieve most of the form info. But unable to identify the css class and styles associated with each field.

I tried to use the class SitecoreSimpleForm, but the css class property is null even if the css exists for that item.

Is there any other way to get the css class value associated with the form elements ?

Thanks in advance..