Variables in JavaScript, as in most languages, can be thought of as named “buckets” that associate names with data that can be used in a program. Information for different variables is stored in memory, which allows you to access that information with a name that points to those data in memory. For example, if you were writing a program that would convert degrees in Fahrenheit to degrees in Celsius, you might store the degrees in a variable in order to do multiple calculations on it.

Listing 2–2. Simple JavaScript Variables

var degrees = 51; var celsius = (degrees - 32) * 5 / 9; console.log(degrees); console.log(degrees * 2); console.log(celsius);

Figure 2–6. Firebug variables

JavaScript variables must begin with a letter, ...

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