Variables are containers for storing data values. They can be used in expressions.

The var statement declares a variable, optionally initializing it to a value.

Variable names can contain letters, digits and underscores. Digits cannot be the first character in the name of a variable. The same rules apply to functions.

The current data types are: number, string, boolean, array, object
The undefined and null data types are special in that they can have only one value.

Undefined variables have been declared but have not been assigned a value.
A variable can be explicitly emptied of its current contents by assigning it the null value.

Default Value: undefined
Example Code
var x = 5 var y = 6 var z = x + y var string = 'example' var example /* From the example above, you can expect: x stores the value 5 as a number data type y stores the value 6 as a number data type z stores the value 11 as a number data type string stores the value example as a string data type example stores the value undefined as an undefined data type */