Computer science is a very young subject, compared to other branches of science that have existed alongside humankind for centuries. One of its main characteristics is that it moves extremely fast. It leaps forward with such speed that, in just a few years, you can see changes that are comparable to real-world changes that took a century to happen. Therefore, as a coder, you must pay attention to what happens in this world, all the time.
Currently, because powerful computers are quite cheap and almost everyone has access to them, the trend is to try to avoid putting too much workload on the backend, and let the frontend handle part of it. Therefore, in the last few years, JavaScript frameworks and libraries, such as jQuery, Backbone and, more recently, React, have become very popular. Web development has shifted from a paradigm where the backend takes...