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

Mastering if Statements in JavaScript

Conditions in JavaScript provide control over the execution flow. While the interpreter executes commands in order, programmers often need to alter this flow based on specific conditions. To achieve this, JavaScript offers two keywords: if and else.

if Statements

The if keyword allows you to open a code block that will be executed if the given condition is true:


              1234567
            
if (true) {
  console.log("It's TRUE!");
}

if (false) {
  console.log("It's FALSE!");
}

In the above example, the if statement executes code only when the condition is true. The syntax of an if statement is straightforward: it begins with the if keyword, followed by the condition enclosed in parentheses (), and a code block enclosed in curly braces {}.

javascript

The opening curly brace { denotes the start of the code block, and the closing curly brace } marks its end.

An expression, as well as a value, can be considered as a condition.


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let a = 935;

if (a > 17) {
  console.log("The variable is greater than 17");
}

if (a > 235124) {
  console.log("The variable is greater than 235124");
}

if (a > 0) {
  console.log("The variable is greater than 0");
}

if (a < 0) {
  console.log("The variable is less than 0");
}

In the example above, when a = 935, there are four conditions:

Condition	Condition result	Code has been executed?
`a > 17`	`true`	Yes
`a > 235124`	`false`	No
`a > 0`	`true`	Yes
`a < 0`	`false`	No

You are not limited to performing operations solely inside the code block:


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let a = 5;
let b = 3;
let c;

if (a > 0 && b > 0) {
  c = a - b;
  console.log("c =", c);
}

if (a > 2 && b > 2) {
  c = a + b;
  console.log("c =", c);
}

console.log(a, b, c);

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Section 4. Chapter 1