The Ultimate Guide To JavaScript ❤️

Okonu Deborah
Jun 20, 2020 · 7 min read
The Ultimate Guide To JavaScript

Nearly all websites employ HTML, CSS, and JavaScript as its primary building blocks. HTML handles the structure of the website, whereas CSS takes care of the designing part. But the site is still static! JavaScript is the soul of the website which breathes life into it.

It is used to make a web page much more interactive and engaging, which results in better user engagement. In fact, without JavaScript, creating an interactive experience for your users can be quite tricky and challenging.

JavaScript is a dynamic computer programming language. It is lightweight and most commonly used as a part of web pages, whose implementations allow client-side script to interact with the user and make dynamic pages.

It is an interpreted programming language with object-oriented capabilities. It is designed for creating network-centric applications. It is complementary to and integrated with Java. JavaScript is very easy to implement because it is integrated with HTML. It is open and cross-platform.

JavaScript is the programming language of HTML and the web.

Brief History Of JavaScript

JavaScript was first known as LiveScript, but Netscape changed its name to JavaScript, possibly because of the excitement being generated by Java. JavaScript made its first appearance in Netscape 2.0 in 1995 with the name LiveScript. The general-purpose core of the language has been embedded in Netscape, Internet Explorer, and other web browsers.

The ECMA-262 Specification defined a standard version of the core JavaScript language. Which are;

  1. JavaScript is a lightweight, interpreted programming language.
  2. Designed for creating network-centric applications.
  3. Complementary to and integrated with Java.
  4. Complementary to and integrated with HTML.
  5. Open and cross-platform

JavaScript and Java are completely different languages, both in concept and design.

JavaScript was invented by Brendan Eich in 1995, and became an ECMA standard in 1997.
ECMA-262 is the official name of the standard. ECMAScript is the official name of the language.

Why Learn JavaScript?

Javascript is a MUST for students and working professionals to become a great Software Engineer especially when they are working in Web Development Domain.

JavaScript is one of the 3 languages all web developers must learn:

1. HTML to define the content of web pages

2. CSS to specify the layout of web pages

3. JavaScript to program the behavior of web pages

Web pages are not the only place where JavaScript is used. Many desktop and server programs use JavaScript. Node.js is the best known. Some databases, like MongoDB and CouchDB, also use JavaScript as their programming language.

Advantages of JavaScript

Below are a few advantages of JavaScript:

  • Javascript is the most popular programming language in the world and that makes it a programmer’s great choice. Once you learned Javascript, it helps you developing great front-end as well as back-end software using different Javascript based frameworks like jQuery, Node.JS, etc.
  • Javascript is everywhere, it comes installed on every modern web browser and so to learn Javascript you really do not need any special environment setup. For example Chrome, Mozilla Firefox, Safari, and every browser you know as of today, supports Javascript.
  • Javascript helps you create really beautiful and crazy fast websites. You can develop your website with a console-like look and feel and give your users the best Graphical User Experience.
  • Due to high demand, there are tons of job growth and high pay for those who know JavaScript.
  • The great thing about Javascript is that you will find tons of frameworks and Libraries already developed which can be used directly in your software development to reduce your time to market.

There could be thousands of reason to learn JavaScript, but one thing you should always know is that, to learn any programming language, you just need to code and code until you become an expert 📌.

The most obvious reason for learning JavaScript is if you have hopes of becoming a web developer. Even if you haven’t got your heart set on a tech career, being proficient in JavaScript will enable you to build websites from scratch — A pretty useful skill to have in today’s world market.

What can JavaScript do?

Below are a few of what JavaScript can do:

  1. It can change HTML attributes
  2. It can change HTML content: One of many JavaScript HTML methods is getElementById(). This method is used to FIND Html elements (with a particular id name) and changes the element content (innerHTML)


document.getElementById(“demo”).innerHTML = 5 + 6;

3. It can change CSS style: Changing the style of an HTML element is a variant of changing an HTML attribute.

document.getElementById(“demo”).style.font-size = “35px’;

4. It can hide HTML elements: Hiding of HTML elements can be done by changing the display style.

document.getElementById(“demo”).style.display = “none”;

5. It can show HTML elements: Showing hidden HTML elements can also be done by changing the display style.

document.getElementById(“demo”).style.display = “block”;

JavaScript code is inserted using the <

JavaScript Functions

A JavaScript function is a set of JavaScript code that can be executed when called for.

A function can be called when an event occurs like when you click on a button.

JavaScript Display Possibilities

JavaScript can display HTML in different ways:

  • Writing into an HTML element using innerHTML
  • Writing into the HTML output using document.write()

Using document.write() after an HTML document is loaded will delete all existing html.

  • Writing into an alert box using window.alert()
  • Writing into the browser console using console.log

For debugging purpose you can call the console.log() method in the browser to display data.

To access an HTML elements, JavaScript uses the document.getElemengById(Id) method.

The I’d attribute defines the HTML elements . The innerHTML property defines the HTML content .

JavaScript Statements

JavaScript statements are composed of:

  • Values
  • Operators
  • Expressions
  • Keywords and
  • Comments

Most JavaScript programs contain many statements. The statements are executed one by one in the same order as they are written.

JavaScript programs/statements are often called “Javascript Code” .


Semi-colon seperates JavaScript statements

JavaScript ignores multiple spaces.

The best place to break a JavaScript statement is after an operator.

JavaScript Synthax

These are a set of rules on how JavaScript programs are executed.

JavaScript Synthax defines 2 values:

  • Fixes values(literals)
  • Variable values (variables).

Rules for writing fixed values:

  1. Numbers are written with or without decimals.
  2. Strings are text written with or without a double or single quote.

Variable values

Variables are used to store data values. JavaScript uses the var keyword to declare variables.

An assignment operator (=) is used to assign values to variables JavaScript uses arithmetic operators (+ — * /) to compute values

JavaScript keyword are use to identify actions to be performed.

For example:

The var keywords tells the browser to create variables.

JavaScript Identifiers

Identifiers are used to name variables (and keywords, and functions and label).

In JavaScript the first letter must be a letter, or an underscore or a dollar sign.

All JavaScript identifiers are case sensitive.

These are just a few introduction on what JavaScript is all about and what you’ll get to see as you dive into learning JavaScript.

I recommend you use w3school, freecodecamp or tutorials point to learn more about JavaScript.

If you Learnt anything from this article, please do well to applaud and follow me and you can as well drop a response too.

Thank y’all for reading. Happy coding!💖💯

Remember it won’t work unless you try📌❤️

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