Discover the essentials of HTML, CSS, and JavaScript to build interactive web applications through hands-on exercises, creating modules like an image carousel and a to-do list.

This course will teach you the fundamentals of creating web applications, from the basics of creating web pages with HTML, stylizing content with CSS, all the way to building interactivity into a page using JavaScript in the browser. 
Instead of watching tedious videos and wondering how to translate those videos into real code, you'll be practicing what you learn through interactive, test-based exercises within minutes. 

Along the way, you'll be able to produce functional modules, including an image carousel and a to-do list application. No prior knowledge is needed.

Learn HTML, CSS, and JavaScript from Scratch

# Context: JavaScript data types

When it comes to programming, pretty much everything we do revolves around *storing* and *manipulating* data. This data always has a **type** associated with it that tells the computer exactly how to handle the data that it's given. In JavaScript, the data's type is *automatically determined* when the code is executed. 
 
What exactly do we mean by this? Let's take a look at an example. 

var number1 = 10; 
var number2 = 20; 

console.log(number1 + number2);


JavaScript looks at the variables declared and determines they are both **numbers**. JavaScript then knows it needs to output the sum of the two numbers to the console. 

JavaScript looks at the variables declared and determines they are both numbers. JavaScript then knows it needs to output the sum of the two numbers to the console.

**Pause and think**: What do you expect this code to do? 

Pause and think: What do you expect this code to do?


> For your reference, `console.log()` outputs to the *console* whatever data is passed to it in between the parenthesis. You can run the code below to see the output.



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# Numbers
Numbers are a numeric data type. Numbers can be integers, floating-point (numbers with a decimal), or exponential values like those you would find with scientific notation. 

All numbers in JavaScript are stored using 64 bits of memory. While delving into how computers represent numbers is out of the scope of this course, it's important to know that there are finite limits to the size of number you can store. 

In practice, this shouldn't be an issue, unless you're working with really, really large numbers. Each bit represents a binary value (e.g., 0 or 1). With 64 bits, the maximal *integer* you can represent is $2^{63} - 1$, or $9223372036854775807$.

# Adding and subtracting numbers
Use the `+` operator to add numbers and the `-` operator to subtract numbers.



Get hands-on experience on how to use numbers as a JavaScript data type. 

Semantic Web Page Layout with HTML

Stylizing HTML Content using CSS

Introduction to JavaScript, Basic Data Types and Operators

JavaScript Program Flow and Data Structures

Building Interactivity with DOM Manipulation

Create a To-do List Application using HTML, CSS, and JavaScript

Wrap Up

Numbers

Context: JavaScript data types