PHP OOP : Constructor function

What is Constructor ?

Constructor is a special type of function of a class which is automatically executed when object of that class is created. Constructor is also called as magic function because in php constructor is start usually with two underscore characters. It saves lot of time on big project.

function __constructor(){
body part;

Example of Constructor :-

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JavaScript : Advantages and disadvantages of External JavaScript ?

Advantages :

Following are the Advantages of javaScript over external :-

  • Reusability of code.
  • Easy code readability.
  • It Enables both web designers and coders to work with html and js files.
  • With these small js files, you can use Google closure or YUI Compressor or other minifying tools to reduce the size and make it not readable by humans .

Disadvantages :

Following are the disadvantages of javaScript over external :-

  • Code can be downloaded using the url of the js file. This can help coders to steal your code easily.
  • If two js files are dependent on one another, then a failure in one file may affect the execution of the other dependent file.
  • A small change to a common js file may cause unexpected results in some of the HTML files .
  • The browser has to make an extra http request to get the js code.
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JavaScript : Where to use javaScript code

JavaScript code use in following :

  1. Between the body tag of html
  2. Between the head tag of html
  3. In .js file (external javaScript)

1. JavaScript use between html body tag :

Example of javaScript using inside html between body tag.

Output :- Hello World

2. JavaScript use between head tag in html :

Example to use javaScript between head tag in html.

Output :

3. External JavaScript file :

We can create external JavaScript file and embed it in many html page. If you want to run the same JavaScript on several pages in a web site, you should create an external JavaScript file, instead of writing the same script over and over again.



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JavaScript : Introduction

JavaScript :

  • JavaScript is used to create client-side dynamic pages.
  • JavaScript (js) is a light-weight object-oriented programming language.
  • JavaScript is not a compiled language, but it is a translated language.
  • The JavaScript Translator (embedded in the browser) is responsible for translating the JavaScript code for the web browser.
  •  JavaScript, users can build modern web applications to interact directly without reloading the page every time.
  • databases such as CouchDB and MongoDB uses JavaScript as their scripting and query language.

Features of JavaScript :

There are following features of js :-

  • Object-Centered Script Language
  • Light Weight and delicate
  • Interpreted language
  • Case Sensitive format/language
  • Ability to perform In Built Function
  • Statements Looping
  • Client edge Technology
  • Validation of User’s Input
  • Else and If Statement
  • It uses prototypes rather than using classes for inheritance.
  • It is supportable in several operating systems including, Windows, macOS, etc.
  • It provides good control to the users over the web browsers.

Application of JavaScript

JavaScript is used to create interactive websites. It is mainly used for:

  • Client-side validation
  • Manipulating HTML Pages
  • User Notifications
  • Dynamic drop-down menus
  • Displaying date and time
  • Displaying pop-up windows 
  • Alert dialog box
  • Confirm dialog box
  • Prompt dialog box
  • Back-end Data Loading
  • Presentations
  • Server Applications
  • Displaying clocks etc.

JavaScript Example :

Output :-

Welcome to JavaScript

Hello JavaScript by JavaScript

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Bootstrap utilities : “Vertical align”

Easily change the vertical alignment of inline, inline-block, inline-table, and table cell elements.

Change the alignment of elements with the vertical-alignment utilities.

These are the classes:- .align-baseline, .align-top.align-middle.align-bottom.align-text-bottom, and .align-text-top as needed.

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How to become a Node.js Developer?


Node.js could be a platform designed on Chrome’s JavaScript runtime for simply building quick and scalable network applications. Node.js uses an event-driven, non-blocking I/O model that creates it light-weight and efficient, excellent for data-intensive time period applications that run across distributed devices.
Node.js is an open-source, cross-platform runtime setting for developing server-side and networking applications. Node.js applications are written in JavaScript and maybe run among the Node.js runtime on OS X, Microsoft Windows, and Linux.

Node.js additionally provides an expensive library of assorted JavaScript modules that simplifies the event of internet applications victimization Node.js to a good extent.

What is Node.js?

Node. js could be a platform designed on Chrome’s JavaScript runtime for simply building quick and scalable network applications. Node. js uses an event-driven, non-blocking I/O model that creates it light-weight and efficient, excellent for data-intensive time period applications that run across distributed devices.

How does Node.js work?

First of all just like other languages node comes with packages and modules. These are libraries of functions that we can import from npm (node package manager) into our code and utilize. Node. js is that the JavaScript runtime surroundings that’s supported Google’s V8 Engine for example with the assistance of Node. js we are able to run the JavaScript outside of the browser js is that it’s single-threaded, supported event-driven design, and non-blocking supported the I/O model.

Why is node js so popular?

Node. js will handle several concurrent requests. this is often the most reason it quickly became popular among developers and huge corporations. It will handle several simultaneous requests while not straining the server.

Role of a Node.js developer:

A Node. js developer is answerable for writing server-side internet application logic in JavaScript and/or variants of it, like CoffeeScript, IcedCoffeeScript, etc, js developer is answerable for writing server-side internet application logic in JavaScript and/or variants of it, like CoffeeScript, IcedCoffeeScript, etc.

Node.js Developer duties:

  • Work as part of a team developing applications and services using Agile development methods.
  • Contribute to team and organizational improvements in process and infrastructure.
  • Build customer-facing UI and back-end services for payment processing administration and management.
  • Code, test, and operate a node. js-based services.
  • Effectively use tools and ingenuity to identify and fix defects before they become a problem.

Responsibilities of Node.js Developers:

Features of Node.js:
Following are some of the important features that make Node.js the first choice of software architects.

Asynchronous and Event-Driven − All Apis of the Node.js library are asynchronous, that is, non-blocking. It primarily means that a Node. the js-based server never waits for an API to come back with the information. The server moves to the next API when calling it and a notification mechanism of Events of Node.js helps the server to induce a response from the previous API decision.

Very Fast − Being built on Google Chrome’s V8 JavaScript Engine, the Node.js library is very fast in code execution.

Single-Threaded but Highly Scalable − Node.js uses a single-threaded model with event looping. The event mechanism helps the server to reply in a non-blocking way and makes the server extremely scalable as against ancient servers that produce restricted threads to handle requests. Node.js uses a single-threaded program and therefore the same program will offer service to a far larger range of requests than ancient servers like Apache HTTP Server.

No Buffering − Node.js applications never buffer any data. These applications simply output the data in chunks.

License − Node.js is released under the MIT license.

The Benefits of Node.js:

  • Better efficiency and overall developer productivity
  • Code sharing and reuse
  • Speed and performance
  • Easy knowledge sharing within a team
  • A huge number of free tools

What is the scope of node JS?

Node.js could be a runtime environment that permits you to write down server-side applications in JavaScript. PHP could be a server-side language. attributable to that, you’ll get to try PHP with a frontend language, sometimes a mix of HTML, CSS, and JavaScript, to make full-stack internet apps.

Node.js Developer Course:

Js Developer Course covers the basics of Node before diving deep into nice tools like specific, Mongoose, and MongoDB. the whole course is predicated around one goal: Turning you into an expert Node developer capable of developing, testing, and deploying real-world production applications.

Node.js Developer requirements and qualifications:

  • Previous working experience as a Node.js Developer for (x) years.
  • BA in computer science or similar relevant field.
  • In-depth knowledge of Node.js.
  • Hands-on experience with HTML, CSS, and AJAX.
  • Development experience designing object-oriented JavaScript and SVG.
  • Applicable knowledge of web libraries and frameworks such as AngularJS, Polymer, and Closure.
  • Familiarity with the whole web stack, including protocols and web server optimization techniques.
  • Strong analytical skills and problem-solving aptitude.
  • Attention to detail.


Node.js is, while not a doubt, one of all the additional interesting technologies in use nowadays, and it’s full-grown into one of all the foremost popular platforms used for internet applications, services, and desktop apps. It’s my hope that when looking at this course, you currently have a solid foundation to begin writing your own Node applications.

If you wanna learn, and from all of us here at DevOpsSchool, thank you for watching!

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How to Become a JavaScript Developer?

Javascript is everywhere. If we are working on a small startup or a large company, most of them do not talk about any kind of website or app that is always on the lookout for someone with Javascript knowledge. There are millions of web pages built on JavaScript and it’s not going anywhere, at least for now.

What is a Javascript Developer?

JavaScript (JS) is a type of web programming language that is supported in all web browsers and devices and is the language that gives JavaScript developers the control and power to create, enhance and modify websites. Some almost 1/3 of all developer jobs JavaScript is required knowledge.

What does a Javascript Developer do?

JavaScript developers are responsible for the programming, development, and implementation of a website, and they may find themselves grappling with the variety of programming duties that go into building websites. They may be responsible for the entire site or only specific aspects or pages of one or more websites.

Web development is a very challenging task that requires a variety of skills such as collaboration, communication, and technical writing.

Role and Responsibility of JavaScript Developer:

  • Troubleshooting and Debugging Applications.
  • Monitoring, Updates, and Security.
  • Server Engineering and Admin Responsibilities.
  • End-User Support and Training.
  • Project Management, Collaboration, Communication.

Essentially, they are responsible for implementing the front-end logic that defines how the visual elements of a web app behave. Typically these developers work on the frontend, closely supported by backend developers and other front-end developers who specialize in markup and styling.

Skill Required for JavaScript Developer:

  • Experience using HTML, CSS, and JavaScript to build dynamic websites or web applications.
  • Experience with React, Angular, or Vue.
  • Strong knowledge of web markup, including HTML5 and CSS3.
  • Strong knowledge of native JavaScript, including ES5, ES6, and a strong understanding of browser compatibility implications.
  • Proficiency with jQuery and Bootstrap frameworks.


JavaScript developer salary largely depends on the role that they occupy and they are in the industry. The average salary of a JavaScript Developer in India is ₹ 6,15,893 to ₹ 12,35,013 per year. JavaScript developers mainly work with frameworks such as Springboot technologies.

Future Scope of JavaScript Developer:

If you are considering a career as a JavaScript developer, you will be pleased to know that JavaScript is one of the most sought-after skills in the programming industry today.

JavaScript is the main force behind the rapidly evolving Internet. It is the present and will be the future. The high-level comprehensive development of the programming language, emphasizing the fact that JavaScript future.

So, if you are planning to become a JavaScript expert, you can expect to be highly employable.

To start with JavaScript, check out the DevOpsSchool course. You’ll learn basic structures and techniques and dive into advanced JavaScript concepts. You’ll even also join our Online and Classroom Programs.

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Top programming languages in the world & their courses and certifications?

The world is turning into smarter day by day with the quick development of Automation, computing, Blockchain, etc. And at the middle of it, somewhere, are programming languages. In fact, Labour Statistics have expected a 21% growth for programming jobs within the returning decade, which is quite 4x the common for all occupations. however attempting to start out out with programming is a frightening escapade, particularly for professionals with no previous expertise. thus if you’re one who cannot decide wherever to start, don’t worry as a result of we’ve got you coated. the following article aims to grant you a fast examine the highest Programming Languages within the world & their courses and certifications?


Owned by the Oracle Corporation, Java is one of the oldest, most typical, in-demand programming languages in use these days. Well, think about a number of your favorite internet apps and games. It’s extremely probably that Java plays an enormous role within the code that creates their work. Another necessary factor that has kept Java’s magic intact among internet development corporations is its independence from platforms. This helps developers to basically “write once, work anywhere”(WORA). Java is everyplace and also the demand for sturdy developers is virtually high.

How does it work?

In Java, programs don’t seem to be compiled into practicable files; they’re compiled into bytecode (as mentioned earlier), that the JVM (Java Virtual Machine) then executes at runtime. Java source code is compiled into bytecode after we use the javac compiler. The bytecode gets saved on the disk with the file extension.

Reasons for Demand:

  • With its presence in almost 3 billion devices, Java’s new frameworks such as Spring, Struts, and Hibernate have also become very popular.
  • It is favored by enterprises, with roughly 90 percent of Fortune 500 companies use Java for building applications and back-end systems.
  • Java is highly recognized for its scalability and portability across multiple platforms from mainframe data centers to smartphones.
  • With millions of users across the globe, the popular users of Java include Barclays, HCL, Capital One, etc.
  • Forms the base for and is used in a multitude of domains including mobile application, web development, system programming, and big data.
  • Its powerful features include strong memory management, high performance, backward compatible and top-notch security.


Developed by the technical school big Google itself, Go is one of the newest players within the programming platform. it’s an open-source language that produces it simple to form easy, secure, and productive computer code. It combines the most effective aspects of useful and object-oriented programming, also as options a valuable set of intrinsical development tools.

How does it work?

Go was originally designed for programs associated with networking and infrastructure. it absolutely was meant to switch widespread high-performance server-side languages like Java and C++. Today, Go is used for a spread of applications like cloud and server-side applications, DevOps, command-line tools, and far additional.

Reasons for Demand:

  • Popular projects like Kubernetes, Docker, Hugo, Hyperledger Blockchain, and Ethereum are developed using Golang.
  • The language is straightforward to grasp even for the new programmers while being extremely powerful at the same time.
  • Supports multithreading at large and is hence used by a lot of companies that rely heavily on distributed systems.
  • Go has been optimized by Google to be incredibly efficient with memory and has blazing fast speed.
  • It provides high performance like C/C++ and has efficient concurrency handling like Java.
  • It is widely used in startups and some of the companies that use the language are Walmart, Springboard, Siemens, Dell.


TypeScript might be a superset of the JavaScript language that has a single open-source compiler and is developed within the main by one trafficker (Microsoft.) The goal of the matter is to help catch mistakes early through a sorting system and to make JavaScript development further economical.

How does it work?

TypeScript works by adding increased syntax to JavaScript so transforming it to JavaScript when the typescript compiler will its own checks. It does not modification JavaScript’s kind of system. Instead, it adds a lot of checks to it.

Reasons for Demand:

  • TypeScript simplifies JavaScript code, making it easier to read and debug.
  • TypeScript gives us all the benefits of ES6 (ECMAScript 6), plus more productivity.
  • TypeScript can help us to avoid painful bugs that developers commonly run into when writing JavaScript by type checking the code.
  • TypeScript is a modern programming language loved by engineers for making web development a lot easier.
  • You can use TypeScript everywhere instead of JavaScript, as it compiles to regular JS code. That’s another reason for its demand.


Scala could be a programming language used for practical programming and powerful static systems. It’s object-oriented and runs on JVM. It’s the aptitude to interoperate with existing Java code and libraries. It’s powerfully thought of to be a static kind of language and doesn’t have an idea of primitive information.

How does it work?

The compiler in Scala works during a similar fashion because of the Java compiler. It gets the source code and generates Java byte-code which will be dead severally on any commonplace JVM (Java Virtual Machine). Scala could be a statically typed language. Scala will execute Java.

Reasons for Demand:

  • Scala programming language variables are immutable and can be easily overloaded in Java. In addition to this, it also offers to adopt new languages like Python, Ruby, etc. to implement functional programming.
  • Scala is a language that is inherently more expressive than Java. The developers who learn Scala after Java find it easier and interesting to write code in Scala. To get the beauty of this language in comparison with Java.
  • A developer needs to be in demand always. The main reason or use of Scala is a better growth and job. Learning Scala will increase your demand and will make you even more marketable. Many companies like Twitter, LinkedIn, Foursquare, etc are using Scala.
  • Scala can be said as a language that is growing fast and lots of programmers going to join the Scala bandwagon. Even developers who know Java are now moving to learn Scala. There are many new libraries and frameworks that are being built on application of Scala.
  • A Java programming finds it difficult to learn any functional language. uses of Scala is easy due to its object-oriented functionality. Scala has clean syntax, nice libraries, good online documentation, and lots of people in the industry using it.


Along with HTML and CSS, Javascript is that the programming language that engineered the internet. So, it’s a fairly huge deal. Universally referred to as the language of internet developers, javascript could be a feature-rich object-based scripting language that includes asynchronous event handling and crisp syntax, it’s found widespread use within the field of internet development. What started off as an easy client-side scripting language, is currently a highlight inside the net development community that includes multiple frameworks for each backend and frontend development.

How does it work?

JavaScript is what’s known as a Client-side Scripting Language. within a standard website, you place some JavaScript code See however sites Work for details on sites. once the browser loads the page, the browser features a constitutional interpreter that reads the JavaScript code it finds on the page and runs it.

Reasons for Demand:

  • In extension to absolute JavaScript, various popular libraries and frameworks make JavaScript development easier.
  • Most accessible supporting technologies related to JavaScript are JSON, jQuery, Angular, React (JS Library), etc.
  • Fundamentally a front-end language, it can also be practiced on the server-side throughout Node.js to create scalable network applications.
  • Majority of tech giants like Google, Facebook, SAP, Dell, Accenture, etc rely on Javascript to design interactive web pages and dynamically display content to users.


PHP is used by 79% of all the websites whose server-side programming language we all know. it’s the main used for developing dynamic and data-heavy websites and applications. it’s been the cornerstone of the net for a protracted time. PHP could be an easy, fast, and platform-independent general programming language with over 631,000 repositories on GitHub.

How does it work?

The PHP software system works with the webserver, which is that the software system that delivers sites to the planet. after you A URL into your net browser’s address bar, you are causation a message to the webserver at that URL, asking it to send you an HTML file. Your browser reads the HTML file and displays the online page.

Reasons for Demand:

  • PHP is used by 79.0% of all the websites whose server-side programming languages are known.
  • PHP is simple, fast and platform-independent.
  • It is 631k repositories on GitHub and has a community of 5.9M to back it up.
  • Companies that have publicly declared usage of PHP include Facebook, Yahoo, Wikipedia.


AngularJS could be a client-side JavaScript MVC framework to develop a dynamic internet application. It extends the flexibility of HTML by adding intrinsical attributes and parts and additionally provides a capability to form custom attributes victimization easy JavaScript.

How does it work?

AngularJS could also be a structural framework for dynamic net apps. It permits you to use hypertext markup language as your model language and permits you to extends HTML syntax to specify your application’s elements clearly and compactly. AngularJS’s information binding and dependency injection eliminate a lot of the code you’d otherwise need to write.

Reasons for Demand:

  • Modularity is one of the prime reasons why AngularJS is popular among web developers.
  • AngularJS recognizes the need to create an additional module so that it can be combined with other developed application modules.
  • It allows and enables web developers to create multiple modules for a single web application.
  • AngularJS is one of the skills unique to this job, along with React. js, Code. js, Javascript, and CSS.
  • Today, AngularJS is a leading framework for building dynamic, single-page web applications (known as SPAs), including ones like PayPal and Netflix.


Node. js is primarily used for non-blocking, event-driven servers, because of its single-threaded nature. It’s used for ancient websites and back-end API services time period was designed with the period of time, push-based architectures in mind.

How does it work?

Node. js is the JavaScript runtime environment which is based on Google’s V8 Engine with the help of Node, Js we can run the JavaScript outside of the browser, js is that it is single-threaded, based on event-driven architecture, and non-blocking based on the I/O model.

Reasons for Demand:

  • A Single Language for All Layers. Another key benefit of Node.
  • It can be Hosted Anywhere.
  • It’s lightning Fast. Node.
  • It is JavaScript Everywhere. One of the biggest reasons why Node.
  • It is Lightweight. Typically, Node.
  • High Performance.
  • It is Easy to Modify and Maintain.


In this article, we have listed the top most popular programming languages to learn. Now, it’s your choice where you want to land your career or choose the right programming language for you, If you wanna learn then i would suggest you check out DevOpsSchool it is a great platform for learning. Get an insight to all the details we mentioned, and choose accordingly. So, make sure you should hold a good command on a specific language you choose for programming.You’ll even also join our Online and Classroom Programs.
And that concludes my list of the Top Programming Languages. Hope this article proved useful to you.

Thank you!

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Tutorial for Polymorphism in OOPS

What is Polymorphism?

Polymorphism, as its name implies, comes in a variety of forms. OOP allows for the use of a variety of techniques I. Simply expressed, they have to do with how methods are used, and how different methods operate for different objects. Method Overriding and Method Overloading are two ways that polymorphic methods allow for different actions to be done.

The benefits of Polymorphism are:

  • Objects of different types can be passed through the same interface
  • Method overriding
  • Method overloading

Method Overriding:- Overriding is used in the polymorphism of runtime. By overriding a parent class’s method, a child class can implement a different method. In the case of our dogs, we may prefer a specific type of bark that is distinct from the generic type of dog (TrackingDog).


TrackingDog’s overriding the bark() method

Method Overloading:- Overloading is used at the polymorphic build time. Although methods and functions may have the same name, the call method has its own set of arguments. Different results may be obtained depending on the number of parameters entered.

Example:- There are no parameters supplied to the updateAttendance() method. The count will be added one day. When the updateAttendance(4) argument is used, the x xupdateAttendance(x) parameter is used, and four days are added to the total.

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Tutorial for Abstraction in OOPS

What is Abstraction?

Basics of Computation Theory. What is "abstraction"? Abstraction unifies  multiple and different objects into one concept  describes the common  properties. - ppt download

Abstraction in OOP allows information/access about how codes are applied to be concealed, allowing just the required access. These details may be found in the object definitions. A famous example is the counting approach that works with list items. One thing to keep in mind is that, given the same OOP concept, all Python I data types and structures are objects. In this sense, a list is a class that has methods for completing tasks.

What is Abstraction in OOPS? - JournalDev

What is the Function of Abstraction?

Abstraction use simpler high-level instruments to get access to a complex object:

  • Using simple things to represent complexity
  • Hide complex details from user
JavaScript ES7 OOP. Abstraction. Class. #1 - YouTube

Abstraction also serves a significant security role. We only present selected data items and provide data access via classes and methods to protect the data from being exposed. In the case of an automobile, an open gas tank would make it impossible to continue driving.

There are some benefits of abstraction which is mention below:

  • Simple, high level user interfaces
  • Complex code is hidden
  • Security
  • Easier software maintenance
  • Code updates rarely change abstraction

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