Please compare functional and non-functional forms of testing?

Following are the important differences between functional testing and non-functional testing:

• Based On – While functional testing is based on customer requirements, non-functional testing is based on customer expectations.
• Defines – Functional testing describes what aspect of a software product. Non-functional testing, on the other hand, defines how the aspect of a software application.
• Order of Performing – Non-functional testing follows functional testing.