Built-in JavaScript objects and functions are ones you'll use all the time. Here's how to use Object, JSON, String, Math, Date, and console in your JavaScript programs.

JavaScript variables hold a wide variety of information and can be used with virtually any data type. Here's how to use variables to store numbers, text strings, objects, and more.

As with almost every programming language, JavaScript treats various types of values differently. A string like “Hello world” is very different from a number like 42. But what types are ...