Summary

JavaScript programming is a problem-solving endeavor. It relies heavily on data and data expressions. At the start of this chapter, we mentioned that data could be people's names, temperature, image dimensions, the amount of disk storage, and total likes on a discussion group post. Data can be values for a user interface, such as screen coordinates, sizes, scroll values, colors, and fonts.

A JavaScript program is a series of steps that use data. A program starts with an event. An event could be when a web browser finishes loading the web page, a mouse event, such as a click or rolling over a spot on the screen, such as a button or image, or when some data is received from a web server that was requested by JavaScript.

Once the program begins, it executes the code statements sequentially and is directed by flow control statements such as if, switch, for, and while.

The code is organized into units called functions. Functions contain code that may need to be repeated...