JavaScript Pocket Reference, 2nd Edition

Chapter 1. The JavaScript Language

JavaScript is a lightweight, object-based scripting language that can be embedded in HTML pages. This book starts with coverage of the core JavaScript language, followed by material on client-side JavaScript, as used in web browsers. The final portion of this book is a quick-reference for the core and client-side JavaScript APIs.

Syntax

JavaScript syntax is modeled on Java syntax, Java syntax, in turn, is modeled on C and C++ syntax. Therefore, C, C++, and Java programmers should find that JavaScript syntax is comfortably familiar.

Case sensitivity

JavaScript is a case-sensitive language. All keywords are in lowercase. All variables, function names, and other identifiers must be typed with a consistent capitalization.

Whitespace

JavaScript ignores whitespace between tokens. You may use spaces, tabs, and newlines to format and indent your code in a readable fashion.

Semicolons

JavaScript statements are terminated by semicolons. When a statement is followed by a newline, however, the terminating semicolon may be omitted. Note that this places a restriction on where you may legally break lines in your JavaScript programs: you may not break a statement across two lines if the first line can be a complete legal statement on its own.

Comments

JavaScript supports both C and C++ comments. Any amount of text, on one or more lines, between /* and */ is a comment, and is ignored by JavaScript. Also, any text between // and the end of the current line is a comment, ...