Course Content

Introduction to JavaScript

1. JavaScript Fundamentals

About JavaScript Understanding JavaScript Syntax Challenge: Console Output in JavaScript Using Comments to Document Code Challenge: Write a Single-Line Comment Challenge: Write a Multi-Line Comment

2. Variables and Data Types in JavaScript

Understanding Variables in JavaScript Challenge: Define the Variable Using const for Constants Exploring JavaScript Data Types Working with null in JavaScript Introduction to Arrays Array Methods and Manipulation Challenge: Perform Array Operations

3. Performing Operations in JavaScript

Understanding Assignment Operators Mathematical Operations in JavaScript Assignment Operators in JavaScript Increment and Decrement Operators Challenge: Variable Operations Practice Comparison Operators in JavaScript Logical Operators Explained Challenge: Compare Variables in JavaScript Concatenating Strings in JavaScript Challenge: Build Sentences with JavaScript

4. Controlling Program Flow with Conditional Statements

Mastering if Statements in JavaScript Using else for Alternative Outcomes Applying else if for Multiple Conditions Challenge: Determine Sizes with Conditionals

5. Looping Through Data in JavaScript

Understanding the while Loop in JavaScript Using the do while Loop for Iteration Challenge: Print Numbers from 5 to 9 Mastering the for Loop in JavaScript Challenge: Console Tigers with Loops Breaking Out of Loops with break Skipping Iterations with continue Challenge: Stop and Skip in Loops

6. Functions in JavaScript

What Are Functions in JavaScript?Defining Functions in JavaScript Challenge: Write a Function – My Name Using Function Arguments Effectively Returning Values from Functions Challenge: Create a Sum Function Course Summary & Next Steps

Using Comments to Document Code

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:


              123
            
console.log("Line 1");
// console.log("Line 2");
console.log("Line 3");

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:


              12345
            
console.log("Line 1");
console.log("Line 2");
// console.log("Line 3");
// console.log("Line 4");
console.log("Line 5");

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


              123
            
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

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:


              1234567891011
            
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");

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


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

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 4

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Course Content

Introduction to JavaScript

1. JavaScript Fundamentals

About JavaScript Understanding JavaScript Syntax Challenge: Console Output in JavaScript Using Comments to Document Code Challenge: Write a Single-Line Comment Challenge: Write a Multi-Line Comment

2. Variables and Data Types in JavaScript

3. Performing Operations in JavaScript

4. Controlling Program Flow with Conditional Statements

Mastering if Statements in JavaScript Using else for Alternative Outcomes Applying else if for Multiple Conditions Challenge: Determine Sizes with Conditionals

5. Looping Through Data in JavaScript

6. Functions in JavaScript

Using Comments to Document Code

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


              123
            
console.log("Line 1");
// console.log("Line 2");
console.log("Line 3");

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:


              12345
            
console.log("Line 1");
console.log("Line 2");
// console.log("Line 3");
// console.log("Line 4");
console.log("Line 5");

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


              123
            
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

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:


              1234567891011
            
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");

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


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

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 4

Introduction to JavaScript

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?

Introduction to JavaScript

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?

Introduction to JavaScript

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?

Introduction to JavaScript

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?

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

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