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JavaScript, along with HTML and CSS, is one of the most important popular programming languages and has changed the landscape of the web development world. The vast majority of websites use it, and all modern web browsers support it without the need for plugins.
It has a sizeable community, and the ecosystem is fast-changing. Today, you need to learn JavaScript to work as a web developer. This post will serve as a guide to give you the best introduction to JavaScript.
JavaScript is a cross-platform, object-oriented scripting language for creating dynamic web pages that have elements like complex animations, clickable buttons, and popup menus. It is often considered the best web browser technology.
There are also complex server-side JavaScript versions and frameworks, such as Node.js, that help when developing new applications. JavaScript frameworks aid in performance and provide ready-to-use solutions. If you're curious about these, check out this article to learn more about JavaScript frameworks.
The JavaScript language can be attached to the objects of its environment inside a host environment - for instance, a web browser window or webpage - to allow programmatic control over them.
A standard library of objects, such as Array, Date, and Math, as well as a basic set of language components, such as operators, control structures, and statements, are included in JavaScript. By extending Core JavaScript with additional objects, it can be used for a variety of applications, such as Client-side and Server-side JavaScript.
Client-side JavaScript adds to the fundamental language by providing objects for controlling a browser's Document Object Model (DOM). Client-side extensions, for example, allow a program to add HTML elements to an HTML file and respond to user actions like mouse clicks, form input, and page navigation.
Server-side JavaScript extends the basic language by providing objects required for server-side JavaScript execution. For instance, it allows application developers to create a connection between the application and the database or support file I/O operations. JSON objects are crucial for this task. But what is JSON?
JSON (JavaScript Object Notation) is a text-based standard for representing structured data based on JavaScript object syntax. It's commonly used in web applications to send and receive data in client and server applications.. Though JSON goes beyond the scope of this article, we recommend you check out this article to learn more about JSON objects and looping to help you get started.
JavaScript is one of the most widely used and dynamic programming languages today, allowing for the construction of rich web experiences for PCs, tablets, and mobile devices. It's a world-class language with a thriving environment and a dedicated community committed to its continued advancement. If you wish to learn JavaScript, here’s a guide to help you get started on JavaScript from scratch.
To get a proper introduction to JavaScript, you must understand the language’s main features. Below we discuss the top 8 features that JavaScript offers.
1. Lightweight
JavaScript is a lightweight scripting language developed mainly for data handling in browsers. Because it is not a general-purpose language, it has a limited number of libraries. The lightweight nature of JavaScript Code is also a good feature because it is only intended for client-side execution, specifically for web apps.
2. Dynamic Typing
Dynamic typing is possible with JavaScript. Dynamic typing means that the data type of a variable is only declared during runtime. This means that programmers do not need to declare the data type of variables while programming, making code simpler and easier to implement.
To declare a variable in JavaScript, we simply use the var or let keyword before the variable name without the need to specify a data type.
3. Object-Oriented Programming
The concept of OOP has been refined, starting with ES6. Object Creation Patterns, or encapsulation. Code Reuse Patterns, or inheritance, are also key aspects of OOP in JavaScript. Although JavaScript developers rarely use this capability, it is available to all users. If you want to learn more, check out this article on the basics of OOP in JavaScript.
4. Functional Style
This means that JavaScript is a functional programming language; even objects are built using constructor functions, and each constructor function represents a different object type. JavaScript functions can also be utilized as objects and given to other functions.
5. Platform Independent
Being platform-independent or portable means that you can write JavaScript code once and run it anywhere at any time. In principle, JavaScript programs can be written and run on any platform or browser without changing the script's output.
6. Prototype Based
Instead of classes or inheritance, prototypes are used in JavaScript. We build a class in a language like Java, and then we construct objects for those classes. However, in JavaScript, we specify an object prototype, which can subsequently be used to generate more objects.
7. Interpreted Language
Scripts written in JavaScript are executed line by line. The JavaScript interpreter, which is a built-in component of the Web browser, interprets these scripts. However, many JavaScript engines in browsers today use just-in-time compilation for JavaScript code.
8. Async Processing
Asynchronous programming is a technique that allows your software to begin a long-running task and then, rather than having to wait for that work to complete, continue to respond to other events while the task is running. These functions are not executed sequentially but rather in parallel, which greatly reduces processing time. When the process is completed, the result is displayed in your software.
JavaScript supports Promise, which allows for asynchronous requests. This ensures that a JavaScript application does not have to wait for other functions in the program to respond, significantly reducing processing time.
You'll undoubtedly feel overwhelmed when you first start learning to code because there are so many new phrases and terms to know. Here are some of the most crucial terminology for beginners for a proper JavaScript introduction, as well as some examples of how to use them in practice!
Methods:
Methods in JavaScript are actions that can be carried out on objects. A JavaScript method is a property that holds the definition of a function.
Libraries:
A library is a JavaScript file that contains functions that can help your website accomplish a specific task. Every Library has its unique set of characteristics. On an as-needed basis, a JavaScript library code can be plugged into the rest of your project's code to improve or introduce new functionalities to your website. Libraries can make your JavaScript code very efficient.
Numbers:
Unlike other programming languages that have integers, floating-point, short, long numbers, etc., JavaScript has only one type of number, which can be either an integer or floating-point. In JavaScript code numbers can be written with or without decimals:
{% code-block language="js" %}let x = 2.14; // A decimals number
let y = 2; // An integer{% code-block-end %}
Larger number in JavaScript can be written with scientific (exponent) notation:
{% code-block language="js" %}let x = 125e4; // 1250000
let y = 125e-4; // 0.0125{% code-block-end %}
Numbers in JavaScript are always stored as double-precision floating-point numbers, which follow the international IEEE 754 standard.
String.length:
A JavaScript string has zero or more characters written inside quotes. In JavaScript, You can use the built-in length method to find the length of the string:
{% code-block language="js" %}
let text = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
let length = text.length; // Output = 26
{% code-block-end %}
Booleans:
A Boolean is a data type in nearly all programming languages representing one of two values: true or false. The Boolean value of an expression forms the basis for all JavaScript comparisons and conditions.
You can use comparison operators in JavaScript to determine if an expression (or a variable) is true or false. Here are some examples:
{% code-block language="js" %}
Operator
Description
Example
==
Equal to
if (number == 5)
>
Greater than
if (age > 18)
<
Less than
if (length < 10)
{% code-block-end %}
Math.random():
It is a method of the JavaScript Math library than can be used to generate random numbers 0 (inclusive), and 1 (exclusive). Math.random() always returns a number lower than 1.
Math.floor():
The floor() method returns a double value that has been rounded down. A mathematical integer will be equal to the rounded value. For example, the value 7.6 will be rounded to 7.0, which is the same as the integer 7.
Math.random() used with Math.floor() can be used to return random integers.
Example:
{% code-block language="js" %}
Math.floor(Math.random() * 10); // Output : a random number between 0 and 9
{% code-block-end %}
Comments:
Comments in a programming language represent a programmer-readable section in the source code that can help explain code functionality. Comments are ignored by compilers and interpreters and can be used to explain and improve the readability of JavaScript code. Comments in JavaScript can also be used to inhibit execution.
Single line comments start with //. JavaScript will not execute any text between // and the end of the line.
Example:
{% code-block language="js" %}
// Initializing a variable: let pi = 3.14;
{% code-block-end %}
Comments that span multiple lines begin with /* and end with */. JavaScript will ignore any text between /* and */.
Example:
/*
Defining multiple variables
For certain function
{% code-block language="js" %}
*/
Let pi = 3.14;
Let randomVar = Math.random()
{% code-block-end %}
Null:
In JavaScript a Null is a special character that represents an empty value or an unknown value. For example:
{% code-block language="js" %}
let x = null;
{% code-block-end %}
The example above suggests that our variable x currently has a null value, which may or may not be initialized to another value later on.
Undefined:
A variable in JavaScript that is declared but its value has not been initialized, then the value of that variable will be undefined.
let Keyword:
This keyword in JavaScript lets you declare variables. However, unlike var variables defined with let cannot be redeclared
Example:
{% code-block language="js" %}
let x = “Jane Doe
{% code-block-end %}
const Keyword:
If variables are declared with the const keyword, they cannot be changed by reassignment after they have been initialized. Thus, When declaring const variables in JavaScript, they must be given a value:
Example:
{% code-block language="js" %}
const PI = 3.14159;
{% code-block-end %}
String Concatenation:
Concatenation is a programming technique for combining two or more strings into a single value. You might, for example, have two lists of employees stored as strings, one for each of your company's branches. You might want to combine them all into a single employee list.
Concatenating a string can be done in two ways: with the + operator or with the concat() method.
Example:
{% code-block language="js" %}
var bill_jhonny = "Bill" + "Jhonny";
console.log(bill_jhonny; // Output : BillJhonny
{% code-block-end %}
The concat() method in JavaScript joins two or more strings together. concat() takes as many parameters as you want, each of which represents a string to be combined. concat() is a method that replaces the concatenation operator.
Example:
{% code-block language="js" %}
var first_name = ‘Mrs.’;
var middle_name = ' John’';
var second_name = ' Doe';
console.log(name_string.concat(middle_name, surname));
// Output : Mrs. John Doe
{% code-block-end %}
Arithmetic Operators:
These operators perform arithmetic on numbers whether they are literals or variables.
{% code-block language="js" %}
Operator
Description
+
Addition
-
Subtraction
*
Multiplication
**
Exponentiation (ES2016)
/
Division
%
Modulus (Remainder)
++
Increment
--
decrement
{% code-block-end %}
Assignment Operators:
They are used to assign values to JavaScript variables. The assignment operator assigns a value after performing some operation. These include +=, -=, and &=.
Example:
{% code-block language="js" %}
let x = 15;
x += 5; // Output : 20
{% code-block-end %}
Variables:
They are containers for storing data or more precisely data values. The 4 ways to declare a JavaScript variable are var, let, const, and nothing.
Template Literals:
Template Literals can be used to define a string with embedded expressions and special constructs. Template Literals use backticks (‘ ’) rather than quotes (" ") which allows you to use single and double quotes inside a string. Multiline strings, variables, and expressions in strings are also possible with template literals.
Example:
{% code-block language="js" %} let price = 20;
let VAT = 0.1;
let total = `Total: ${(price * (1 + VAT)).toFixed(2)}`;. {% code-block-end %}
Template literals allow the addition of variables and expressions into strings. The method is called string interpolation.
The syntax is:
${...}
A script is a program or sequence of instructions written in a scripting language's syntax and interpreted or executed by another program rather than the computer processor (as a program is compiled).
Scripting languages are programming languages that allow you to write scripts. Scripts are evaluated directly by a runtime environment (in this case, a script engine), unlike source files for other programming languages, which must be compiled into bytecode before being run.
The vast majority of scripting languages use dynamic typing. This enables you to create new variables without defining their type (the interpreter assigns the type based on the type of the object associated with the variable). It also allows you to reuse the same variable for different types of objects (type conversion is performed automatically).
With 97% of websites utilizing it for this purpose, JavaScript language is the most popular client-side scripting language on the Internet. Scripts interact with the document object model via being embedded in or included in HTML code documents (DOM).
Every major web browser has a built-in JavaScript engine that executes code on the user's device, allowing you to implement complex features on web pages — whenever a web page displays timely content updates, interactive maps, animated 2D/3D graphics, and so on — you can bet that JavaScript is involved.
If you want to learn more about JavaScript, here are tips that will help you become a better JavaScript developer.
Understanding scripting rules is an integral part of writing JavaScript Following are the main JavaScript syntax and scripting rules:
Yes! JavaScript is very simple to use. Simply paste your code into an HTML document and inform the browser that it is JavaScript.
With the use of asynchronous processing, JavaScript allows you to design extremely responsive interfaces that improve the user experience and give dynamic functionality. It's quick and flexible, and its browser support functions can even assist in identifying and resolving issues. As a result, JavaScript has a strong presence in the development community and is an important skill for any aspiring web programmer.
If you’re interested in growing your technical skillset, you should take the time to learn to write JavaScript code. There are several resources available for it since it is the most popular programming language. Here are the 5 best ways to learn the JavaScript language fast.
1. Self-Guided Websites and Courses
Above all else, the Internet is a knowledge treasure trove. If you prefer self-directed study or simply don't have the time to enroll in a formal program, flexible online courses may be the educational solution.
These free and paid online courses will show you how to learn JavaScript quickly, but remember that "free" does not always imply "better." Free programs frequently lack direction and support compared to their paid counterparts. Make sure you do your homework before enrolling in your first class! All this will help you tremendously to get a good JavaScript introduction.
2. Books
A famous saying is, “When in doubt, read a book.” There are many books that can teach you how to program, but some are even more useful for aspiring programmers who want a quick introduction to JavaScript.
3. Coding Schools and Bootcamps
Perhaps self-education isn't for you. While you know you could learn from an on-demand self-guided course or the activity chapters of a book, you'd like a little more support and guidance throughout your educational journey. A coding school or bootcamp maybe your best option in such a scenario.
Coding bootcamps have risen in popularity in recent years to obtain marketable skills rapidly and without committing to the time or money required by standard four-year school programs. A typical bootcamp lasts between a few weeks and a few months, depending on whether the bootcamp is part-time or full-time.
However, If you are focused and want to pursue coding, coding schools are the right choice. The most significant difference between coding bootcamps and schools is that the latter is more prolonged and intensive, providing a way to learn and apply real-world skills. Coding schools connect students worldwide, allowing you to engage in a diverse and driven community and get life-changing experiences. For some, this is the best option, which is why Microverse, a global, online school for software developers exists.
4. Coding Meetups and Networking Events
When it comes to the greatest ways to learn JavaScript, "networking" is not the first answer that comes to mind, but it is one of the most beneficial. Attending meetups and networking events can have a huge educational impact. Attend a JavaScript panel if you want to learn the language rapidly. You'll be able to learn from folks who have extensive experience with it. However, the learning does not stop with the presentation; it continues in the ensuing interactions.
You may believe that you are fine on your own, but it is satisfying to assist others. Simply by assisting others, you may learn new things and gain new perspectives.
Sometimes the best way to learn JavaScript is to speak with others who are learning, exploring, and achieving with you, rather than sitting with your nose to the grindstone or in a book.
5. Starting Your Own Projects
What was the point of learning something in the first place if you didn't put it into practice? At some point, aspiring developers will need to move away from tutorials and into real-world programming. But the transition isn't always easy.
Moving beyond the safe confines of step-by-step assignments and creating an app from scratch can be daunting. However, if you keep looking for tutorials, you'll never be able to use your imagination or take your first steps into independent development. Programming is the most effective way to learn how to code, but you don't have to start with a large project right away.
Start small. After you have got an adequate introduction to JavaScript and are ready to put your JavaScript skills to work on a real project, rather than starting from scratch, try adding a feature to a program you made in a tutorial.Alternatively, you might start with a pre-existing foundation and work your way up from there . Consider working on a project with a friend if you require assistance.
The first attempt to remove the tutorial training wheels is always the most difficult but is also the most rewarding. If you are having trouble getting started, here is a beginner’s tutorial on how to implement an anagram in JavaScript to help you get started.
After mastering the basics of JavaScript, you should focus on learning more advanced topics such as classes, scopes, maps, sets, iterables (arrays and strings), and loops (while and for). These will further enhance your skills and make you a pro at JavaScript. These concepts are also very well summarized in a cheatsheet too.
All in all, most of the applications we see today, with amazing visuals and features, use JavaScript. Web developers prefer it across the globe because of its premium features and ease of use. Want to learn more about JavaScript? Here are 10 Advanced JavaScript Challenges.
Ariel is the founder & CEO of Microverse, an online school for software engineers. Read more about Microverse and how it can help you.
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