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

Comparison Operators in JavaScript

Comparisons are used to define conditions, perform checks, and make decisions in JavaScript. These operations return a boolean value (true or false), which other operators use to determine certain actions.

Comparison Operators

JavaScript offers several comparison operators for comparing values:

Equal to (==);
Strict Equal To (===);
Not Equal To (!=);
Strict Not Equal To (!==);
Greater Than (>);
Greater Than or Equal To (>=);
Less Than (<);
Less Than or Equal To (<=).

Equal and Not Equal

The Equal To operation (==) returns true if the first value equals the second value and false otherwise.

Conversely, the Not Equal To operation (!=) returns true if the values are unequal.

Example:


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console.log("Equal to:");
console.log("5 == 5 is", 5 == 5);
console.log("5 == 4 is", 5 == 4);
console.log("5 == 4.99 is", 5 == 4.99);
            
console.log("Not equal to:");
console.log("5 != 5 is", 5 != 5);
console.log("5 != 4 is", 5 != 4);
console.log("5 != 4.99 is", 5 != 4.99);

Note

The = operator is for assignment, while == is for comparison. Be careful to distinguish them.

Strict comparison

Strict comparison checks the types of values and values. The Strict Equal To (===) operator returns true - if both the values and their types are the same, while !== returns true if they are different.

Example:


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console.log("5 === 5 is", 5 === 5);
console.log("5 === '5' is", 5 === '5');
console.log("5 == '5' is", 5 == '5');

console.log("5 !== 5 is", 5 !== 5);
console.log("5 !== '5' is", 5 !== '5');
console.log("5 != '5' is", 5 != '5');

console.log("Type of 5 is", typeof(5));
console.log("Type of '5' is", typeof('5'));

Greater and Less

The Greater Than (>) operator returns true if the first value exceeds the second. Conversely, the Less Than (<) operator returns true if the first value is less than the second.

Example:


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console.log("5 > 5 is", 5 > 5);
console.log("5 > 4.99 is", 5 > 4.99);
console.log("5 > 5.0000001 is", 5 > 5.0000001);

console.log("5 < 5 is", 5 < 5);
console.log("5 < 4.99 is", 5 < 4.99);
console.log("5 < 5.0000001 is", 5 < 5.0000001);

Greater/Less Than or Equal to

The Greater Than or Equal To (>=) and Less Than or Equal To (<=) operators combine the corresponding comparison operators with Equal To (==). They return true if either of the conditions is satisfied.


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console.log("5 >= 5 is", 5 >= 5);
console.log("5 >= 4.99 is", 5 >= 4.99);
console.log("5 >= 5.0000001 is", 5 >= 5.0000001);

console.log("5 <= 5 is", 5 <= 5);
console.log("5 <= 4.99 is", 5 <= 4.99);
console.log("5 <= 5.0000001 is", 5 <= 5.0000001);

Note

The >= operator combines > and ==, not ===. The <= operator works similarly.

1. What will be the output?

2. What will be the output?

3. What will be the output?

4. What will be the output?

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Section 3. Chapter 6