Summary  
This chapter explains how to use single-line (`//`) and multi-line (`/* ... */`) comments to disable sections of code and leave notes for documentation or debugging.

General domain of usage  
Code documentation

Comments let you hide parts of your code from being executed. They are useful when you want to temporarily disable code or leave notes for yourself or other developers.

Comments are ignored by the interpreter and are helpful for documentation.

Note

# Single-line Comments (`//`)
Single-line comments ignore everything on the same line.

console.log("Line 1");
// console.log("Line 2");
console.log("Line 3");

Only the commented-out line is skipped.

You can also comment multiple consecutive lines:

console.log("Line 1");
console.log("Line 2");
// console.log("Line 3");
// console.log("Line 4");
console.log("Line 5");

console.log("Part 1.1"); console.log("Part 1.2");
console.log("Part 2.1"); // console.log("Part 2.2")
console.log("Part 3.1"); console.log("Part 3.2");

# Multi-line Comments (`/* ... */`)
Use multi-line comments when you want to disable larger sections of code.

console.log("Line 1");
console.log("Line 2");
/*
console.log("Line 4");
console.log("Line 5");
console.log("Line 6");
console.log("Line 7");
console.log("Line 8");
console.log("Line 9");
*/
console.log("Line 11");

Everything between `/*` and `*/` is ignored.

Multi-line comments can also hide part of a line:

console.log("Part 1", /* "Part 2", */ "Part 3");

/* console.log("Part 4"); */ console.log("Part 5");

What is the syntax for creating a multi-line comment?

If you have a large code block and enclose it within `/*` and `*/`, what happens to the enclosed code?

Learn the fundamentals of JavaScript, the backbone of dynamic web development. Discover essential concepts like syntax, variables, data types, and operators. Explore how to use conditional statements, loops, and functions to create interactive and efficient programs. Master the building blocks of JavaScript and lay the groundwork for more advanced programming skills.

Discover the fundamentals of JavaScript, including its purpose and syntax. Learn how to work with the console for output and use comments to organize and document your code. These foundational skills will prepare you for a deeper exploration of JavaScript's capabilities.

Explore the building blocks of JavaScript by distinguishing between literals and variables. Understand the core data types, including `null` and arrays, and learn how to manipulate them using array methods.

Learn how to manipulate JavaScript's data types through essential operations. Master assignment, mathematical operations, incrementing and decrementing, comparisons, logical operations, and string concatenation.

Discover how to control the flow of your programs with conditional statements. Master `if`, `else`, and `else if` to instruct JavaScript on making decisions and executing code based on different conditions.

Streamline your code by mastering JavaScript's looping structures. Explore `while`, `do while`, and `for` loops, and learn how to control their behavior using `break` and `continue`. Unlock the power of loops to perform repetitive tasks efficiently.

Discover the power of functions in JavaScript. Learn how to define functions, work with arguments, and use the `return` statement to create reusable and efficient code. Mastering functions will enhance your ability to write clean and modular programs.

Using Comments to Document Code

Single-line Comments (`//`)

Multi-line Comments (`/* ... */`)

1. Why are comments used in code?

2. How do we create a single-line comment?

3. What is the syntax for creating a multi-line comment?

4. If you have a large code block and enclose it within `/` and `/`, what happens to the enclosed code?