Chapter 4. Variablesvariable is a name associated with a value; we say that the variable stores or contains the value. Variables allow you to store and manipulate data in your programs. For example, the following line of JavaScript assigns the value 2 to a variable named i: i = 2; And the following line adds 3 to i and assigns the result to a new variable, sum: var sum = i + 3; These two lines of code demonstrate just about everything you need to know about variables. However, to fully understand how variables work in JavaScript, you need to master a few more concepts. Unfortunately, these concepts require more than a couple of lines of code to explain! The rest of this chapter explains the typing, declaration, scope, contents, and resolution of variables. It also explores garbage collection and the variable/property duality.[1] Chapter 5, Chapter 6, and Chapter 7 before returning to finish up the remainder of this chapter. |