Introduction to JavaScript

Introduction to JavaScript

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1. Basic Concepts

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.

About JavaScript

Challenge: Console Output

Challenge: Single-line Comment

Challenge: Multi-line Comment

2. Variables and Data Types

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.

Challenge: Defining the Variable

Data Types Overview

Challenge: Array Operations

3. Basic Operations

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

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

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.

if

Challenge: Determining Size

5. Loops

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.

Challenge: Printing Numbers from 5 to 9

Challenge: Tigers

Challenge: Stopping and Skipping

6. Functions

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.

What is a Function?

Challenge: My Name

Contenido del Curso

Introduction to JavaScript

Introduction to JavaScript

if

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:


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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 {}.

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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Sección 4. Capítulo 1

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