The Responsive Web Design makes reference to web programming and web design to suit the user's environment, especially to your screen.
However there are objective data that should bring the client to understand why we prefer to program in PHP and not in other languages such as asp.
W3 Techs performs a continuous study which is the use of every programming language in a million of the world's most popular websites, a study that is updated daily.
In November 1st 2012, 78.3% of websites used PHP, being for a long time the first choice for web developers. Using this language, indeed free and without licenses, provides excellent security to customers that can switch providers more easily. Furthermore, this language has gained 1.4 points of market share in the last year, mainly at the expense of asp.net.
Asp.net with a 20.7% share is the second most popular choice, even at a great distance, and has lost a market share of 1.2 points in 2012.
n summary, in LA TEVA WEB we do prefer first analyze the project before deciding the programming language to use but experience leads us to almost always end up opting for PHP.