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.
The following two types of comments are allowed:
Single line comments start with
//and end at the end of the line.Multiline comments start with
/*and end with*/on the same line or any subsequent line. Note that any code in between the comment start and the comment end is ignored.
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.