Comments (JavaScript: The Definitive Guide, 4th Edition)

2.5. Comments

JavaScript, like Java, supports both C++ and C-style comments. Any text between a // and the end of a line is treated as a comment and is ignored by JavaScript. Any text between the characters /* and */ is also treated as a comment. These C-style comments may span multiple lines but may not be nested. The following lines of code are all legal JavaScript comments:

// This is a single-line comment.
/* This is also a comment */  // and here is another comment.
/*
 * This is yet another comment.
 * It has multiple lines.
 */