How do I block form submits from public ISP (free) emails?

If you want to prevent form submits from public emails like Yahoo, Gmail or AOL you can set it up in ActiveDEMAND form editor.

Step 1: Open the form and edit the Email Address field by clicking the pencil icon:

Step2: In the EDIT FORM FIELD menu choose the Custom CSS Class and type "nofreeemail" :

Next time if someone uses a public email, there will be a message "Please use your company email address. Public email addresses (Gmail, Yahoo, and AOL) are not allowed":