Introduction to JavaScript
Prerequisites for this course is a little bit of knowledge about HTML and elements in HTML. This course focuses on giving a brief guide on various aspects of JavaScript like the Introduction, Scopes, Needs, etc., and not on coding part.
I would like to put “Why do we need JavaScript?” before all the other topics. Understanding the need of existence will make some sense when it comes first.
Why do we need JavaScript?
Back in the 1990s, there was an outbreak of a specific technology called the Internet. As you know the internet is a global network of interconnected computers which can send and receive data to other computers. You can request for a resource and a computer will give to you. For example, when you visit the URL, the HTML page will be served. Early days people used the internet for advertising their companies, with websites built using only HTML and CSS. Not a great one but did the job. But as time goes, people needed websites to be more attractive and interactive. So, some developers in Netscape (If you haven’t heard about it, it’s a big deal in olden days) decided to write a language to manipulate the HTML elements in the browser. Thus, born JavaScript. Please understand JavaScript and Java are not related. It’s just named in that way for marketing the language. I hope this section gave you an idea of what requirement or need led to the creation of JavaScript.
What is JavaScript?
Simply to put, JavaScript is a programming language for the web which can be used to update both HTML and CSS, it also performs all the logic, so you can do validations, calculations, manipulation of data.
Note: JavaScript is a scripting language.
It doesn’t need any compilation and rather needs interpretation. Why? When you compile a language, it will be converted into native code and native code cannot be executed by other computers with different CPU architectures. But scripting language is written to compile by other programs, like a browser. So, send it as a code to any browser, which then reads it line by line and interpret and execute it.
Why should we use JavaScript?
Although we have many client languages for the browser for HTML manipulation like VBScript and coffee script, why we mainly use JavaScript? Why it’s a born winner? Why not replace JAVASCRIPT with other scripting languages? The reasons are
- It is what every other browser supports.
- Most of the client languages they built use JavaScript as an intermediate.
- It is easy to learn compared to other scripting languages.
You can take out the JavaScript, but it involves a lot of cost and damage to the internet. The only reason we are not letting it rest in peace.
Understanding JavaScript
In this section, we will focus on the coding part. Let’s get our hand dirt by coding,
<html>
<body>
<h1></h1>
<!-- Pray the old gods! -->
<script type="text/javascript">
var myHeading = document.querySelector('h1');
myHeading.textContent = 'Hello, world!';
</script>
</body>
</html>
Here, we completely used JavaScript to manipulate an h1 HTML element and changed its property. We used a script tag to put code inside HTML. You may not understand the document.querySelector is. You don’t need to understand what each line does, just follow up me. Copy paste the above code to an HTML file and open it in the browser. You will see the following output.
What just happened?
First using a function called document.querySelector (), you grab a reference to your heading in your HTML page and store it in a variable called heading. After that, you’ve set the value of the heading variable’s textContent property (which represents the content of the element) to “Hello world!”, which changes that specific element.
This HTML file is what sent to the client machine, and it will be interpreted line-by-line and executed. (Just like how you watch each frame in a movie)
How does JavaScript make working so easy?
- JavaScript evolved more than what we saw now, it will continue to evolve and will have more feature in the future. Recent development like React, React Native showed us how it can be super effective used.
- In recent years it is modified to run in a server environment (node.js). Frontend developer can easily understand backend, so a developer from a frontend background and understand the logic of backend easily.
- This language is an old pal. It’s been here for many years and it will continue to be here, and its community is very big, so you get good support.
- Many frameworks and libraries are developed using core JavaScript, which makes common functionalities easy to implement.
- It is a dynamic language designed to optimize programmer efficiency, so you can implement functionality with less code.
Note: A static language (C, C++, etc.) is designed to optimize hardware efficiency so that the code executes as quickly as possible.
- It is one of the easiest programming languages to learn. Please try out VBScript then you will know why JS is one of the easiest languages.
<html>
<body>
<!-- Notice that type property of script element is changed to text/vbscript -->
<script type="text/vbscript">
document.write("Yes!!! I have started learning VBScript.")
</script>
</body>
</html>
Top JavaScript companies
- Netflix – Movies & TV shows the online streaming company
- Trello – Trello is a web-based list-making application
- PayPal – Online payment system
- LinkedIn – LinkedIn is a business and employment-oriented website.
- Walmart – A retailer
- Uber – Taxi booking app
- E-bay – A e-commerce website.
What you can do with JavaScript?
You can do many things, literally many things with the JavaScript.
- Websites – Obvious, this is why we invented this language. In websites, it is used to add interactivity to HTML elements.
- Server Applications – Node.js changed the way we use JavaScript. Now this language is used in building server. Node.js capability to build scalable web apps.
- Mobile Apps – React Native is used to creating mobile apps with JavaScript.
- Smartwatch apps – React Native is used to creating mobile apps with JavaScript.
- Robots and IoT– Yes, you’ve read that right. With a minimal OS, NodeJS can be installed and this means you can use JavaScript environment to code Robots.
- Johnny-Five – For robotics and IoT platform.
- Cylon JS – Robotics kit
- Games – You can use any language to code a game. But with HTML5 canvas and JavaScript as browser-based games will be super cool.
- Machine learning – With AI being state of the art on current technologies, how can JavaScript stay out of the ring?
- TensorFlow is now available on JavaScript
- Brain JS for building Neural Nets
- Compromise for natural language processing
Scope of JavaScript
According to recent GitHub stats, It is one of the widely used languages. Why? It is available in all platform frontend, backend, graphics designing, etc. The Scope of JavaScript is very wider as it comes into major play for web development.
Here are some scopes,
- Become as a website developer – It allows you to build websites interactively and beautifully if you want to go as a web developer, this is a go-ahead language for you. It has become an operating power of web technology along with HTML and CSS, as most browsers implement JavaScript Engine in it.
- Become as a frontend developer – With this language, you can learn to React, Angular, or Vue.JS with ease.
- Become as a backend developer – If you want to become a backend developer then try learning NodeJS, Language is similar, but the way it works internally is different. Knowing JS and knowing Node JS is different. But syntax is all same.
- Become as a Mobile developer – Furthermore, It has now extended to mobile app development for IOS and Android with hybrid development concept, desktop app development, and game development. All in all, now it is a very useful skill to learn if you want to go as a web developer. But, also knowing the native development favors you in a tough situation or building a complex future. If you learn react-native you will be a mobile developer, but if you also learn native development, then you will become an unleashed mobile developer. Also, you don’t need to develop separate apps for IOS and Android. Just do single time code and it can run on multiple platforms.
- Become as a tester – Frameworks like Jest, Selenium let the language to conquer testing also.
- Become as an API developer – Become JSON as one of the most used data types in APIs, JAVASCRIPT has native support for it making a better suit for building services.
- Become as a game designer – Now it supports 3D modeling with three.js. You can see some of the cool stuff listed on their website. As a game designer, you can develop a high graphics game in the web environment. You can also venture into game development for web apps by JavaScript.
- Become as an IoT developer – You can use JS to code Arduino and circuits
- Become as a data scientist – Want to become a data scientist for a web development background? JavaScript is there to save! As we have seen many libraries are used for Neural Network creation and development
There are many such things you can become with JavaScript. It will even have more scope in future as it’s a core web technology. When web evolves, JavaScript also evolves with it.
Required skills
You can do basic function with JavaScript, but these are some good-to-have features for you if you want to become a good developer.
- Asynchronous programming using promises or async/await
- Writing cross-browser codes, same behavior on multiple browsers
- Efficient memory management. when it comes to UI, it needs to be faster. People don’t like slow UIs. With only efficient memory management we can optimize the performance of the application.
- Variable scopes understating
- Closures
- Higher-Order Functions
- Arrow functions
- Responsive web designing
- Socket programming with PUB/SUB flow
- Document object model (DOM) and Browser object model (BOM)
- ECMA Script 3 and 5
- Prototype and inheritance
- Functional programming
- Basic understanding of HTTP-based APIs
Who is the right audience for learning JavaScript technologies?
There are no such things call the right audience for learning. But, to whom its suites a lot? If you are an absolute beginner in programming, you can start with JavaScript. If you want to become trend-developer learning React, React Native or Node, you should first concentrate on understanding JavaScript. Take your time to understand JavaScript. Then you should be able to understand most of the JavaScript-based frameworks.
How this technology will help you in career growth?
Let the number speak now!
React usage
All frameworks are based on JS, you can see that React and Angular stays on top. If you study React or Angular, JS won’t let you down.
Node JS jobs
Node JS is a backend platform, Jobs posting for Node JS as a backend is increased in time as you see the graph.
JavaScript usage
JavaScript usage is rocketed. Usage denotes demand for the language. The demand is increased, and everyone started learning JavaScript, usage also increased.
From the graph you can say that it is one of the languages for 2018, but what happens next? We don’t know. In my opinion, Golang will do great in the future. Let’s see.
Conclusion
Let’s do this straight. A language which is created to add beauty to websites evolved into something we never thought of. Now it’s everywhere, literally everywhere. In 2018, React and Node JS which is based on JavaScript is most loved frameworks. It contains all the fundamental things for the current trends like frontend and backend. Now, for learning the purpose, it is a suitable language to start learning to code. Once you start learning it, you will get a basic understanding of all languages. You can start without any knowledge of programming at all with JavaScript.
It is undoubtedly the dominant language of the web. You can see it is still on the top competing with new languages. Tough old beast, isn’t it? Having that in mind please also update yourself with other languages. It’s safe to say there will be no shortage of JavaScript opportunities in 2019 and beyond.
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