Comments

One last thing for this chapter: comments. Inside your JavaScript program, you can put comments. These are ignored by the JavaScript engine and don't have any effect on how the program works. But, they can be invaluable when you revisit your code after a few months, or transfer the code to someone else for maintenance.

Two types of comments are allowed:

Some examples are as follows:

// beginning of line

var a = 1; // anywhere on the line

/* multi-line comment on a single line */

/*
  comment that spans several lines
*/

There are even utilities, such as JSDoc and YUIDoc, that can parse your code and extract meaningful documentation based on your comments.