This book tells you how to make computers do what you want them to do. Computers today are as common as screwdrivers - but contain many more hidden complexities and are therefore harder to understand and operate. For many, they remain alien, slightly threatening things.

We have discovered two effective ways to reduce the communication gap between us, the watery biological organisms with a talent for social communication and long-form reasoning, and computers, the emotionless manipulators who work with meaningless data. The first is to tap into our sense of the physical world, and build interfaces that mimic it so that we can use our fingers to manipulate shapes on the screen. For simple interaction with the computer, this is good.

But we haven't found a good way to convey to the computer, using mouse movements and clicks, things that the interface designer did not provide for. In order to interact with a computer at more complex levels, such as assigning arbitrary tasks to it, our talent for communication is better suited: we teach the computer a language.

Human languages allow you to combine words in a great variety of ways, so that we can say so many different things. Computer languages are structured in much the same way, although they are less flexible grammatically.

Over the past 20 years, working with a computer has become very common, and interfaces built in language (and once it was the only way to communicate with a computer ) are almost replaced by graphic ones. But they are still there - if you know where to look for them. One such language, JavaScript, is built into almost every web browser and is therefore available on almost every computing device.

This book aims to give you enough familiarity with this language so that you can make your computer do what you need.