The term separation of concerns was probably coined by Edsger W. Dijkstra in 1982. Separation of Concerns (SoC) refers to the ability to identify, encapsulate and manipulate the software parts relevant to a particular concern. It has emerged as one of the important principles in Software Engineering. Separation of Concerns (SoC) is the principle for better control of software complexity, during development, maintenance and reuse. The main goal of SoC is the ability to deal with a concern (aspect) separately, during maintenance. A good SoC policy is useful to increase software quality and decrease the effort to test, maintain, understand, reuse and document software. For example, in object-oriented paradigm the separated concerns are modeled as objects and classes and in structural paradigm, concerns are represented as procedures(ISO 9241,1998). One of the most important concerns used in web applications is Usability.