For some time now, you could have noticed a trend in web applications development to build more and more complicated applications, moving more logic from the server to the client side. Is it an appropriate trend? I don’t know. The discussion between supporters and opponents of each approach may look like discussion concerning superiority of Easter over Christmas; it’s hard to concede the point to any side as they have their arguments. That is why, this article won’t be another for or against argument in this dispute. However, I’ll attempt to answer the question whether a well-known object-oriented programming approach may be successfully adopted to the client-side programming.