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Medium Javascript: Javascript Explained

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Javascript is a high-level programming language that enables web developers to create content and dynamic applications on the web. It is a powerful and easy-to-use language that is used in web development, web applications, server-side scripting, games, and more. If you are new to web development and want to learn Javascript, this guide will provide an overview of the main concepts that you need to understand.

Introduction to Javascript and Its Uses

Javascript is a programming language that has been widely adopted by web developers worldwide since its introduction in 1995 by Netscape. It is a scripting language that helps developers create dynamic, interactive content and applications on web pages. It is used for a variety of applications including webpages, games, server-side scripting, and more. As an interpreted language, Javascript is easy to read and write compared to other programming languages.

Javascript has become very popular due to its flexibility and simplicity, and has grown to become one of the most popular and widely used programming languages. It can be used in combination with HTML and CSS to create websites and web applications, or can be used on its own to develop browser-based applications. It is also becoming increasingly popular for server-side scripting, due to its capabilities such as a built-in HTTP client and other useful libraries.

Javascript is also used for mobile application development, as it is supported by most mobile browsers. It is also used for creating desktop applications, as it can be used with frameworks such as Electron. Additionally, it is used for creating Internet of Things (IoT) applications, as it can be used to control hardware devices.

Javascript Variables, Objects and Functions

Javascript variables are used to store values during execution of the program. A variable within a program must be declared before it can be used and acted upon. Objects in Javascript are used to store collections of related data. The properties of an object are the data stored within it. Objects are useful for grouping data and making your code easier to read. Javascript functions are blocks of code created with the purpose of executing a specific task. They take in any number of parameters and return a value after being called.

Understanding the Benefits of Using Javascript

Javascript is a powerful language because it is open source, runs in all major browsers, can be used for both client-side and server-side scripting, and has a wide range of libraries available that make complex tasks easier. Using Javascript allows you to develop applications faster, save time, and reduce the cost of development. It also enables developers to easily create cross-browser compatibility and allows for dynamic, interactive content on webpages.

Working with Arrays and Loops in Javascript

An array in Javascript is an ordered list of values, like a list or collection of data. Javascript supports several types of arrays including numeric, associative, and multidimensional. Arrays can be used to store data or manipulate data by using functions such as push, pop, shift, unshift, and more. Arrays are key to writing efficient code, as they allow you to loop through data quickly without having to hardcode values or write extra lines of code.

Loops in Javascript allow you to iterate over an array or other data structures such as an object. By using loops, you can execute the same block of code multiple times without having to hardcode each iteration separately. You can also use them to traverse over an array or object and build HTML strings for output. The main types of loops available in Javascript are for, while, do-while, for-in and for-of.

Writing Code in Javascript

When writing code in Javascript, you must adhere to certain coding conventions. Such conventions include using comment blocks to structure your code and adding descriptive variable names. In addition to defined standards such as spacing and indentation, coding conventions also provide clarity when it comes to writing efficient code. Writing code in Javascript is also made easier with a wide range of libraries available that make certain tasks easier such as manipulating HTML strings or working with AJAX requests.

Troubleshooting Common Javascript Issues

Debugging code in Javascript can be difficult due to the dynamic nature of the language. It is important to be familiar with debugging tools such as the console log, breakpoints, and the debugger statement. It is also important to understand error messages generated by the console in order to determine the source of an issue. Common issues in Javascript can be classified as syntax errors which arise due to invalid code structure or type errors which occur when a variable of an incorrect type is used.

Interacting with the DOM Using Javascript

The Document Object Model (DOM) is used to define the logical structure of an HTML or XML document. It represents a tree structure of elements which developers can interact with using Javascript. Interacting with the DOM involves methods such as getElementById(), querySelector(), createElement(), appendChild(), setAttribute(), and more. These methods are essential for building user interfaces and making applications interactive.

Working with Libraries and Frameworks in Javascript

In addition to working with HTML provided by browsers, developers often use libraries and frameworks in their code. Libraries provide a set of functions that make certain tasks easier such as working with AJAX requests, generating HTML strings, manipulating data sets, etc. Frameworks on the other hand are used to structure your code into manageable chunks. Popular libraries include jQuery, Underscore.js, React, AngularJS and more.

Using ES6 Features in Your Code

The latest version of Javascript (ES6) introduced a range of new features that make development more efficient and easier. Such features include let and const instead of the var keyword; classes; enhanced object literals; arrow functions; promise syntax; iterators and generator functions; template strings; spread operator; rest parameters; destructuring; promises; async functions; modules; and more.

Developing Cross-Browser Compatible Applications

Developing applications that are compatible across all major browsers is essential for successful web development. Although most modern browsers have similar implementations for many features and commands, there are often discrepancies between the way that different browsers interpret the same code. Development tools such as Gulp or Grunt can be used to minify code automatically for compatibility across different clients. Additionally, cross-browser testing is necessary.

Debugging and Testing Your Code

Debugging your code is an essential part of development that ensures that any errors are corrected before releasing an application in production. Debugging techniques such as line-by-line debugging and setting breakpoints help identify errors quickly. Automated testing tools such as Jasmine help ensure accuracy in coding and minimise bugs further. Understanding the debugging techniques available and writing meaningful tests should help make development more efficient.

Deploying Your Application

Once an application has been completed it needs to be deployed so that users are able to access it. Deployment requires setting up web hosting or cloud hosting services such as Amazon Web Services or Microsoft Azure. Once the hosting environment has been set up the application can then be uploaded using FTP or an IDE such as NetBeans or WebStorm.


This guide has provided a comprehensive overview of Javascript including its fundamentals, benefits, libraries and frameworks, debugging techniques, coding conventions, deployment considerations and more. As an open-source language that enables developers to create powerful content and applications quickly, it is no surprise that Javascript has become one of the most popular programming languages today.

Nisha Kumari

Nisha Kumari

Nisha Kumari, a Founding Engineer at Bito, brings a comprehensive background in software engineering, specializing in Java/J2EE, PHP, HTML, CSS, JavaScript, and web development. Her career highlights include significant roles at Accenture, where she led end-to-end project deliveries and application maintenance, and at PubMatic, where she honed her skills in online advertising and optimization. Nisha's expertise spans across SAP HANA development, project management, and technical specification, making her a versatile and skilled contributor to the tech industry.

Written by developers for developers

This article was handcrafted with by the Bito team.

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