Comments

A programming is used for a computer to understand. Comments are used by developers to help clarify the meaning of your code in a human-friendly language.

In JavaScript, a comment is any text after a double forward slash if you want to write comments one line at a time like this.

要寫一行的 comment 可以用兩個 slash

If you know you're going to write a block of comments. Using a slash star and star slash.

要寫一堆 comment 可以用 /* */

Comments are not executed by Javascript interpreter so you can write useful and helpful comments.

The comments make us easier to remember what this code was originally for.