JavaScript employs data types to characterize the kind of data that variables can handle. These include number, string, boolean, null, undefined.

The type of a JavaScript variable is dynamically determined by its value, allowing the type to change in accordance with its value.

JavaScript has special types: 'undefined' and 'null'. Each has only one value. 'undefined' means that a variable has been declared but does not yet have a value. 'null' implies the absence of a value. Note that we will use a special console.log method, which outputs the result in the console.