Comments

Sometimes, you may need to prevent a specific part of your code from executing. Deleting the entire code isn't convenient if you want to test a separate section later. There are various scenarios where you may need to temporarily halt the execution of a non-working part of your code. In such cases, comments come to your rescue.

Note
Comments provide a syntax for hiding sections of your code from the interpreter or compiler. They are also valuable for documenting code for other developers.

Single-line Comments

Single-line comments block the entire line of code, ensuring that the code above and below them is executed. The syntax for single-line comments is straightforward: you need to add // before the code on the line you wish to comment out:

The example above shows that the comment // blocks the second code line, which is not executed.

We can also use single-line comments to block multiple lines of code in a row:

Also, we can add the comment at the end of the line.

Multi-line Comments

Consider a situation with a large code block, 299 lines long. Commenting each line individually would be time-consuming. That's where multi-line comments come in handy.

Multi-line comments start with /* and end with */. Any code enclosed within them is commented out:

In the example above, we can see that code line from 3 to 10 hasn't been executed.

We can use multi-line comments to comment a part of the line:

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?

Why are comments used in code?

Select the correct answer

To increase the length of the code.

To execute specific sections of code.

To hide sections of code from the interpreter.

How do we create a single-line comment?

Select the correct answer

Add /* before the code.

Add // before the code.

Place code within curly braces {}.

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

Select the correct answer

/* before and */ after the code.

/ before the code.

' before and ' after the code.

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

Select the correct answer

It remains unaffected.

It is executed.

It is commented out.

Everything was clear?

Section 1. Chapter 4

Course Content

Introduction to JavaScript

1. Basic Concepts

About JavaScript Syntax Challenge: Console Output Comments Challenge: Single-line Comment Challenge: Multi-line Comment

2. Variables and Data Types

Variables Challenge: Defining the Variable const Data Types Overview null Array Array Methods Challenge: Array Operations

3. Basic Operations

Assignment Mathematical Operations Operations with Assignment Increment and Decrement Challenge: Variable Operations Comparison Operations Logical Operations Challenge: Comparing Variables String Concatenation Challenge: Sentence Building

4. Conditional Statements

if else else if Challenge: Determining Size

5. Loops

while do while Challenge: Printing Numbers from 5 to 9 for Challenge: Tigers break continue Challenge: Stopping and Skipping

6. Functions

What is a Function?Definition Challenge: My Name Arguments return Challenge: Sum Summary

Comments

Note
Comments provide a syntax for hiding sections of your code from the interpreter or compiler. They are also valuable for documenting code for other developers.

Single-line Comments

The example above shows that the comment // blocks the second code line, which is not executed.

We can also use single-line comments to block multiple lines of code in a row:

Also, we can add the comment at the end of the line.

Multi-line Comments

Consider a situation with a large code block, 299 lines long. Commenting each line individually would be time-consuming. That's where multi-line comments come in handy.

Multi-line comments start with /* and end with */. Any code enclosed within them is commented out:

In the example above, we can see that code line from 3 to 10 hasn't been executed.

We can use multi-line comments to comment a part of the line:

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?

Why are comments used in code?

Select the correct answer

To increase the length of the code.

To execute specific sections of code.

To hide sections of code from the interpreter.

How do we create a single-line comment?

Select the correct answer

Add /* before the code.

Add // before the code.

Place code within curly braces {}.

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

Select the correct answer

/* before and */ after the code.

/ before the code.

' before and ' after the code.

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

Select the correct answer

It remains unaffected.

It is executed.

It is commented out.

Everything was clear?

Section 1. Chapter 4