JavaScript comments are an essential part of any programming language. They allow developers to leave notes for themselves and others, explaining what the code does and why certain decisions were made. In JavaScript, there are two types of comments: single-line and multi-line.

Single-line Comments

Single-line comments start with two forward slashes //. Any text following // on the same line is a comment.

Here’s an example:

// This is a single-line comment
let x = 5; // You can also place comments after code

In the above example, // This is a single-line comment and // You can also place comments after code are both single-line comments.

Multi-line Comments

Multi-line comments start with /* and end with */. Any text between /* and */ is a comment, even if it spans multiple lines.

Here’s an example:

/*
This is a multi-line comment.
You can write as much as you want here.
*/
let y = 10;

In the above example, the text between /* and */ is a multi-line comment.

Why Use Comments?

Comments are crucial for maintaining your code. They can:

1. Improve code readability: Comments can explain what your code does, making it easier for others (and future you) to understand.
2. Help in debugging: If your code isn’t working as expected, comments can help you remember what each part of your code is supposed to do.
3. Provide documentation: Comments can serve as a form of documentation for your code, explaining the purpose of functions, classes, and variables.