WHAT IS JAVASCRIPT

JavaScript, often abbreviated as JS, is a programming language that conforms to the ECMAScript specification. JavaScript is high-level, often just-in-time compiled, and multi-paradigm. It has curly-bracket syntax, dynamic typing, prototype-based object-orientation, and first-class functions.

JavaScript is a scripting or programming language that allows you to implement complex features on web pages — every time a web page does more than just sit there and display static information for you to look at — displaying timely content updates, interactive maps, animated 2D/3D graphics, scrolling video jukeboxes, etc. — you can bet that JavaScript is probably involved. It is the third layer of the layer cake of standard web technologies, two of which (HTML and CSS) we have covered in much more detail in other parts of the Learning Area.

• HTML is the markup language that we use to structure and give meaning to our web content, for example defining paragraphs, headings, and data tables, or embedding images and videos in the page.
• CSS is a language of style rules that we use to apply styling to our HTML content, for example setting background colors and fonts, and laying out our content in multiple columns.
• JavaScript is a scripting language that enables you to create dynamically updating content, control multimedia, animate images, and pretty much everything else. (Okay, not everything, but it is amazing what you can achieve with a few lines of JavaScript code.)

The three layers build on top of one another nicely. Let’s take a simple text label as an example. We can mark it up using HTML to give it structure and purpose:

<p>Player 1: Chris</p>

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Then we can add some CSS into the mix to get it looking nice:

p {
  font-family: 'helvetica neue', helvetica, sans-serif;
  letter-spacing: 1px;
  text-transform: uppercase;
  text-align: center;
  border: 2px solid rgba(0,0,200,0.6);
  background: rgba(0,0,200,0.3);
  color: rgba(0,0,200,0.6);
  box-shadow: 1px 1px 2px rgba(0,0,200,0.4);
  border-radius: 10px;
  padding: 3px 10px;
  display: inline-block;
  cursor: pointer;
}

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And finally, we can add some JavaScript to implement dynamic behavior:

const para = document.querySelector('p');

para.addEventListener('click', updateName);

function updateName() {
  let name = prompt('Enter a new name');
  para.textContent = 'Player 1: ' + name;
}

The core client-side JavaScript language consists of some common programming features that allow you to do things like:

• Store useful values inside variables. In the above example for instance, we ask for a new name to be entered then store that name in a variable called name.
• Operations on pieces of text (known as “strings” in programming). In the above example we take the string “Player 1: ” and join it to the name variable to create the complete text label, e.g. ”Player 1: Chris”.
• Running code in response to certain events occurring on a web page. We used a click event in our example above to detect when the button is clicked and then run the code that updates the text label.
• And much more!

What is even more exciting however is the functionality built on top of the client-side JavaScript language. So-called Application Programming Interfaces (APIs) provide you with extra superpowers to use in your JavaScript code.

APIs are ready-made sets of code building blocks that allow a developer to implement programs that would otherwise be hard or impossible to implement. They do the same thing for programming that ready-made furniture kits do for home building — it is much easier to take ready-cut panels and screw them together to make a bookshelf than it is to work out the design yourself, go and find the correct wood, cut all the panels to the right size and shape, find the correct-sized screws, and then put them together to make a bookshelf

Javascript Features

JavaScript is one of the most popular languages which includes numerous features when it comes to web development. It’s amongst the top programming languages as per Github and we must know the features of JavaScript properly to understand what it is capable of.

Some of the features are lightweight, dynamic, functional and interpreted. Now we are going to discuss some important features of JavaScript.

• Light Weight Scripting language
• Dynamic Typing
• Object-oriented programming support
• Functional Style
• Platform Independent
• Prototype-based
• Interpreted Language
• Async Processinghttps://3ef1b049105050cd04ec6e72911e6e71.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html
• Client-Side Validation
• More control in the browser

Let’s see all of these features in detail so that you can understand them. Some of the above-specified features are old JavaScript features while some of them are new features.

1. Light Weight Scripting Language

JavaScript is a lightweight scripting language because it is made for data handling at the browser only. Since it is not a general-purpose language so it has a limited set of libraries. Also as it is only meant for client-side execution and that too for web applications, hence the lightweight nature of JavaScript is a great feature.

2. Dynamic Typing

JavaScript supports dynamic typing which means types of the variable are defined based on the stored value. For example, if you declare a variable x then you can store either a string or a Number type value or an array or an object. This is known as dynamic typing.

To understand this, in languages like Java, we explicitly mention that a particular variable will store a certain type of data, whereas in JavaScript we do not have to provide the data type while declaring a variable. In JavaScript, we just have to use var or let keyword before the variable name to declare a variable without worrying about its type.

3. Object-Oriented Programming Support

Starting from ES6, the concept of class and OOPs has been more refined. Also, in JavaScript, two important principles with OOP in JavaScript are Object Creation patterns (Encapsulation) and Code Reuse patterns (Inheritance). Although JavaScript developers rarely use this feature but its there for everyone to explore.

4. Functional Style

This implies that JavaScript uses a functional approach, even objects are created from the constructor functions and each constructor function represents a unique object-type. Also, functions in JavaScript can be used as objects and can be passed to other functions too.

5. Platform Independent

This implies that JavaScript is platform-independent or we can say it is portable; which simply means that you can simply write the script once and run it anywhere and anytime. In general, you can write your JavaScript applications and run them on any platform or any browser without affecting the output of the Script.

6. Prototype-based Language

JavaScript is a prototype-based scripting Language. This means javascript uses prototypes instead of classes or inheritance. In languages like Java, we create a class and then we create objects for those classes. But in JavaScript, we define object prototype and then more objects can be created using this object prototype.

7. Interpreted Language

JavaScript is an interpreted language which means the script written inside javascript is processed line by line. These Scripts are interpreted by JavaScript interpreter which is a built-in component of the Web browser. But these days many JavaScript engines in browsers like the V8 engine in chrome uses just in time compilation for JavaScript code.

8. Async Processing

JavaScript supports Promise which enables asynchronous requests wherein a request is initiated and JavaScript doesn’t have to wait for the response, which at times blocks the request processing. Also starting from ES8, Async functions are also supported in JavaScript, these functions don’t execute one by one, rather they are processed parallelly which has a positive effect on the processing time, reducing it to a great extent.

9. Client-side Validations

This is a feature which is available in JavaScript since forever and is still widely used because every website has a form in which users enter values, and to make sure that users enter the correct value, we must put proper validations in place, both on the client-side and on the server-side. JavaScript is used for implementing client-side validations.

10. More control in Browser

JavaScript being a client-side language provides many features that help developers to divide processing between browser and server hence reducing the load on servers by having basic processing, validations, temporary data saving using cookies, etc on the browser itself.

Along with all these features, JavaScript provides the following useful features too:

• Detecting browser type, name OS version, etc information of the client for analysis.
• Extensive in-built library with many useful functions for validation, data type conversion, string operations, etc.
• It is an object-centered language with Window Object being the most important object in JavaScript and it also supports Polymorphism.
• Support for commonly used complex data types like array, Maps, List, etc. with support of in-built functions to operate on them.

WHAT IS WEB DEVELOPMENT?

Web development is the building and maintenance of websites; it’s the work that happens behind the scenes to make a website look great, work fast and perform well with a seamless user experience.

Web developers, or ‘devs’, do this by using a variety of coding languages. The languages they use depends on the types of tasks they are preforming and the platforms on which they are working.

Web development skills are in high demand worldwide and well paid too – making development a great career option. It is one of the easiest accessible higher paid fields as you do not need a traditional university degree to become qualified.

The field of web development is generally broken down into front-end (the user-facing side) and back-end (the server side). Let’s delve into the details.

Comparing Front-End and Back-End Development

A front-end dev takes care of layout, design and interactivity using HTML, CSS and JavaScript. They take an idea from the drawing board and turn it into reality.

What you see and what you use, such as the visual aspect of the website, the drop down menus and the text, are all brought together by the front-end dev, who writes a series of programmes to bind and structure the elements, make them look good and add interactivity. These programmes are run through a browser.

The backend developer engineers what is going on behind the scenes. This is where the data is stored, and without this data, there would be no frontend. The backend of the web consists of the server that hosts the website, an application for running it and a database to contain the data.

The backend dev uses computer programmes to ensure that the server, the application and the database run smoothly together. This type of dev need to analyse what a company’s needs are and provide efficient programming solutions. To do all this amazing stuff they use a variety of server-side languages, like PHP, Ruby, Python and Java.

What about Full-Stack Development?

If both Frontend and Backend development appeal to you, you could consider becoming a fullstack developer.

Full-stackers take care of both the front-end and the back-end, and need to know how the web works on all levels, in order to determine how the client- and server-sides will relate. Naturally working up to this level of expertise will take longer, as there is more to learn.

Getting Started in Web Development

All this may sound daunting at first, but you don’t need to know everything at once. You will grow your knowledge progressively. And things will begin to click. 

The great news is, learning to become a developer is easily accessible and affordable. This is especially true with OpenClassrooms. Emily Reese, Web developer and Teacher at OpenClassrooms explains,

Whatever aspect of web development attracts you, we have programs that can help you reach your goals.

No matter your background, you can learn web development. Emily told us,

In undergrad, I studied art history and architecture and then decided to become a developer whilst I was working at Kickstarter because I saw how the web could complement creativity in the arts. The same is probably true for any field.

Becoming a web professional allows you to participate in absolutely any field, because the web has become universally present in our professional lives. You can be a web developer and specialize in anything from the art world to the automobile industry.

The first step is to decide which aspect of web development interests you and then start out with one programming language.

For example, if you are interested in front end you can start by learning some HTML and CSS, then start working on projects as soon as you are comfortable with the basics. Ourweb development programme is a perfect fit for this route. But others may suite you as well.

It also helps to join a discussion group or community of other web developers, so that you can troubleshoot, discuss ideas and get inspiration. That’s why you become part of the OpenClassrooms community when you 

IMPORTANCE OF JAVASCRIPT IN WEB DEVELOPMENT

What is JavaScript and why is it important in web development?

JavaScript is a programming language used primarily by Web browsers to create a dynamic and interactive experience for the user. Most of the functions and applications that make the Internet indispensable to modern life are coded in some form of JavaScript.

Javascript is one of the powerful and flexible programming languages. It is one of the core technologies of World Wide Web. It is popular among developers as JS. The programming language is essential for developing web applications.

You can easily develop web applications using the JavaScript. According to 2018 Stack Overflow survey, it is voted as the most popular language by developers.

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