What is JavaScript and how is it used?

Javascript is a programming language. It is a scripting language that lets us control multimedia within our web pages. It empowers a developer to do many things like adding animation to our images or updating content automatically on a page. 

For example, if you’re on a web page that has a shopping cart powered by JavaScript, you’ll notice that it immediately shows the total cost of what you want to buy including taxes, shipping, etc. Javascript is then used when determining whether the credit card details you entered were valid before transferring those details across the net to the bank for processing. 

THE language of the web

Javascript is now THE language of the web. For years it was only run in browsers to operate on HTML. It also runs on servers and is as powerful as many of the programming languages you’ll encounter.

JavaScript is among the world’s most used programming languages. Without it, we’d be looking at pages that do nothing other than display images and text. So while CSS may be what offers style to a website, JavaScript (JS) is what gives it life.

Without this amazing language, businesses would be at a loss. Companies depend on languages like this to interact with their customers in today’s world.

What is JavaScript?

JavaScript is what allows you to interact with the vast majority of web pages that you visit. Whether it’s filling out forms, scrolling through maps, or registering for an event, it’s most likely that JavaScript is what’s allowing you to do it. 

Using a human form metaphor, HTML is what gives a skeleton to all of our features. It supports the head and the body of a person. CSS is what gives us our style, or our features, like the colour of our skin, eyes and hair. JavaScript is to do with our movements and how we interact with others – like when we reciprocate a handshake, wink, laugh or ask a question.

What is JavaScript used for?

It’s vitally important for all industries, especially since we are now in an age where data is power. While it’s not the JavaScript that holds all of this data, it is what allows it to be manipulated in the browser. It’s the language that creates the functions needed to interact with a company through its website.

JavaScript enables users to fill out forms, click buttons and more. Without it, businesses would be at a significant loss. Check any job listing website for the term “JavaScript”. For example, a simple search on Indeed in the UK shows 14,453 vacant roles at the time of writing. In the Dutch version of Indeed, the number is 5,136.

How to use JavaScript

Web browsers are built to understand HTML and CSS and convert those languages into a visual display on the screen. To do this, the browser uses what’s called a layout or rendering engine. This is the part of the web browser that understands HTML and CSS.

A browser also contains what’s called a JavaScript interpreter. This is the part of the browser that understands JavaScript and can execute the steps of a JavaScript program.

A web browser is usually expecting HTML. But we must specifically tell the browser when JavaScript is included. To do this, we use the <script> tag. This is similar to the <style> tag used in CSS. Also, like CSS, Javascript can be included in the head element or accessed from an external file. Javascript doesn’t have to be confined to the head element, though. You can also insert script elements in the body area, creating islands of behaviour or functionality throughout the page.  

Developers often recommend that you place your javascript as the last element inside the body of a page. This is because javascript mainly operates on HTML elements as part of a task.  

Javascript is designed to be able to travel the element family tree or DOM and access, modify, add or even delete elements. If the javascript appears in the head of a page, it might attempt to access elements that the browser has not yet interpreted. That is, they might not yet have been added to the family tree in memory. These elements need to have first been read by the browser interpreter for javascript to access them on the tree.

JavaScript Syntax

Learning a programming language is like learning any spoken language. There are words to learn and rules to be followed. For example, if you wanted to learn Spanish, you would have to learn the grammatical rules before you can speak it fluently. So, with JavaScript, there are grammar-type rules that you will have to learn. Once you know the fundamentals of one programming language, you know many of the fundamentals of all.

JavaScript allows us to interact with the Document Object Model directly. In our example, we access the document object. When a developer loads an HTML document into a web browser, it’s at that stage that it becomes a document object.

The document object is the root node of the HTML document and the “owner” of all other nodes or elements. The document object provides properties and methods to access all node objects within JavaScript.

In our example, we use the document object to write to the screen twice. The first time we write some HTML formatted text to the screen. The second time we write the sum of two numbers to the screen.

Javascript uses what is called dot notation. On the left, we see a word called “document”. This word represents the document object both to the developer and the browser. A dot then follows it, then another word with parentheses and some text inside the parentheses. Everything after the dot is called a function. A function does something. The name tells us what the function does. In this case, it will write something to the screen. The text inside the parentheses is what will be evaluated and written to the screen.

This illustrates Javascript’s ability to work with and even create HTML elements on the fly. And secondly to perform tasks such as mathematical operations.

Notice that this content is added dynamically. That is, when the page is created, there are no elements inside the body tags. Only when the page is run in a browser does the Javascript run.

JavaScript Jobs

So, are there opportunities for people who can use JavaScript? Well, here’s the thing, most companies with an online presence (which is pretty much every company) needs Javascript. The problem for businesses is that the number of companies that require these skills far outweighs the number of people who actually have these skills.

As a result, the demand for Javascript developers is incredibly high. In fact, in general, the need for software developers is so high that governments worldwide have digital upskilling strategies in place to ensure that the workforce is ready for future business needs. This is what we call “the digital skills gap”. This is what is creating JavaScript opportunities.

The digital skills gap

Even before Covid-19 arrived, the demand for developers was huge. In Europe, the prediction was that there would be a need for more than 700,000 extra digitally skilled workers by the year 2020. Well, we’re well beyond 2020 now. A recent report from the World Economic Forum – which they created in October 2020 – suggests that by 2025, automation and technology will displace 85 million current roles. However, herein lies the extra opportunity for career changers. The WEF predicts that 97 million more-technology focused roles will replace these roles. 

JavaScript Salaries

Javascript is both a front end and a back end language. However, it is the most popular front-end language globally. With data being more valuable than gold, companies use it to allow their end-users to interact with them. Because of the lack of javascript developers, salaries for these skills are proving high. This is even the case for brand new developers.

For example, in the UK, Morgan McKinley’s salary calculator estimates that JavaScript developers with between 0-3 years experience can earn anywhere from £35,000 per annum to £70,000. In Ireland, Morgan McKinley reckons the same expertise can attract a salary of between €40,000 and €50,000. Not a bad figure for somebody who is starting anew in a career. Meanwhile, in the Netherlands, Honeypot reckons a new Javascript developer can earn between €38,000 and €42,000.

In Europe and the UK in general, it is clear that developers earn a high salary, even from entry-level. But, of course, these high salaries are not just unique to Javascript programmers. For example, suppose you’ve learned Python in the UK and are looking for a job. In that case, Morgan McKinley reckons a Python developer with between 0-3 years experience can earn between £40,000 and £70,000. Similarly, in Ireland, they estimate new Pythonistas as earning between €40,000 and £50,000.

JavaScript – in demand

If you’ve been contemplating a change of career, software development is one of the most in-demand roles in the world. No matter what industry you’re looking at, there is a need for developers to build the technologies, websites, and more.

Learning a skill like JavaScript under your belt is massively advantageous if you want to change your career. Front-end developers are needed everywhere. But, of course, what’s even better is having the skills to handle a full-stack. That means having skills in both front end and back end software development. HTML, CSS, and JavaScript make up much of the front end, while other languages and technologies, like Python, Flask, MongoDB, Django, and many others, assist in making up the backend.

5 Day Coding Challenge – learn JavaScript basics

Code Institute’s free 5 Day Coding Challenge can offer you some insights into HTML, CSS & JavaScript. The best thing about the challenge, other than learning the basics, is that it’ll let you know if you have an aptitude for software development. Register for this weekly challenge through the form below. Alternatively, if you want to learn more about our Full Stack Software Development programme, follow this link

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