Introduction

JavaScript is the programming language of the Web. It is the language for HTML, for the Web, for computers, servers, laptops, tablets, smart phones, and more.

JavaScript is a case-sensitive language. This means that language keywords, variables, function names, and other identifiers must always be typed with a consistent capitalization of letters. The while keyword, for example, must be typed “while,” not “While” or “WHILE.” Similarly, online, Online, OnLine, and ONLINE are four distinct variable names.