Submitted by Bumhan Yu
JavaScript has five primitive data types: string(in double- or single-quotation marks), number (only floating point numbers--this type includes NaN), Boolean, undefined, and null. Everything else is considered an object which includes arrays, functions, and objects.
All primitive and object type data can be assigned to variables and be performed on a variety of operations. Arrays are used for storing collections of data, where each item is called an element and identified by its index. Array has a .length property and a series of helper methods and iterator methods for accessing/manipulating data.
