JavaScript Language: Basics Guide For Beginners

JavaScript is a high-level, dynamic and scripting computer programming language.

It is lightweight and most frequently used as part of web pages, the implementation of which allows client-side scripts to communicate with the user and create dynamic pages.

It is also an interpreted, object-oriented programming language.

JavaScript was first known as LiveScript. But Netscape changed its name to JavaScript, probably due to Java's enthusiasm.

In 1995, JavaScript produced its first appearance with the name LiveScript in Netscape 2.0. Netscape, Internet Explorer and other web browsers have embedded the language's general-purpose core.

History of JavaScript

JavaScript was created by Brendan Eich in 1995, which appeared in Netscape, a popular browser of the time.

 

The language was first called LiveScript and later JavaScript. Many programmers believe JavaScript and Java are the same. JavaScript and Java are actually very different.

 

Java is a complicated programming language, while JavaScript is a scripting language only. JavaScript syntax is mainly influenced by the language C of the programming.

 

Run JavaScript

You don't have to worry about using Google Chrome, Internet Explorer, Firefox or any other web browser, JavaScript is supported all.

 

Javascript Tools Offline

• Webstorm
• Atom
• CodeLobster
• Komodo Edit

You need to begin a text editor to write your code and a browser to show the web pages you are developing.

You can use your preferred text editor, including Notepad++, Visual Studio Code, Sublime Text, Atom, or any other text editor that you are comfortable with.

 

You can use any web browser that includes Google Chrome, Firefox, Microsoft Edge, Internet Explorer, etc.

 

Run JavaScript Online

• Js.do
• Tutorialspoint.com
• Rextester.com

 

 

Hello World JavaScript Program

If you keep your JavaScript code in the HTML document itself, you should place all of your JavaScript code within <script> tags (<script> and </script>). This enables your browser to differentiate your JavaScript code from the remainder of the code.

Since there are other scripting languages on the client-side (Example: VBScript), it is highly recommended that you specify the scripting language you are using.

You must use the type attribute within the < script > tag and set the value to text/javascript as follows:

 <script type="text/javascript">
  alert("Hello World!");
 </script>

Basic of JavaScript Programming

HTML provides a special <SCRIPT> tag allowing developers to embed JavaScript within the page markup.

The variable declaration using the JavaScript var keyword is very simple and does not have a complicated set of initialization rules, as can be found in Java or C++.

JavaScript is known as the untyped language, so that variables may be used as a program in a variety of forms.

JavaScript Functions vs. Methods

The contents of the <SCRIPT> tag may either be code to be invoked as soon as a user encounters the <SCRIPT> tag or it may contain JavaScript functions.

JavaScript functions are similar to what other languages would call methods. These JavaScript features contain code that can be triggered by a browser-based case such as a mouse click, page load, submission of type or keystroke.

It is also common to invoke another JavaScript function to perform additional work.

Modern JavaScript Libraries

The basic JavaScript engine with a modern browser only provides an important and basic set of APIs for the development of software. A lot of code requires to be written to perform complex functions, such as applying an Ajax-based request-response cycle or even performing advanced DOM parsing or string manipulations.

 

The fact that differences exist between each major vendor in which versions of JavaScrpt they are implementing, and in the bug-free way these implementations, further complicates the task of writing code to achieve common yet complex programming tasks.

Use the var keyword of JavaScript to declare variables

Because it is permissible for a variable named greeting to be created as a text string type String to change on the fly into a type integer variable, JavaScript is known as a weakly typed language.

In a strongly typed language such as C++ or Java, this sort of variable conversion would cause a compilation error.

Historically, the var keyword was used to initiate a variable declaration.

However, the variable may end up with a larger scope when the Var keyword is used than originally intended to cause conflicts with other parts of the code that may declare a variable similarly named.

JavaScript and Java

A common misunderstanding is that JavaScript is similar or closely connected with Java. It is true that they both have a syntax similar to the C language.

They are also typically both sandboxed (when used in a browser), and JavaScript was designed with Java's syntax and standard library in mind. In specific, all keywords in JavaScript original have been reserved; a normal JavaScript library follows Java naming conventions, while objects in JavaScript math and dates are based on Java 1.0 classes but the similarities end there.

Both Java and JavaScript first appeared in 1995. But Java was developed by James Gosling in Sun Microsystem and JavaScript by Brendan Eich in Netscape Communication.

The differences between these two languages are more prominent than their similarities. Java has static typing while the typing of JavaScript is dynamic.

Java is loaded from the compiled bytecode, while JavaScript is loaded as the source code readable by the human. The objects of Java are class-based, while those of JavaScript is prototype-based.

Finally, Java did not support functional programming until Java 8, whereas JavaScript was influenced by Scheme from the beginning.

Use of JavaScript

There are many uses of JavaScript in the programming language. JavaScript used in

1. Web Development

JavaScript is a language for client scripting that is used to create web pages. It is a stand-alone language created in Netscape. It is used to make a webpage dynamic and add special effects on websites such as rollover, roll-out, and many kinds of graphics. It is mostly used by all websites for validation purposes.

2. Web Application

Browsers and personal computers have improved to the extent that a language was needed to create robust web applications. When a user explores a map in Google Maps, the user just has to click and drag the mouse.

3. Server Application

Node JS is designed to run on Chrome's Javascript to create quick, scalable network applications. It uses event-driven, lightweight and effective apps to be dispersed with a server via the devices. Javascript is used to manage HTTP requests and to generate content.

4. Web Server

A web server can be developed using JS Node. The benefits of Node JS are that it is event-driven and would not wait for the earlier call's reaction.

5. Games

Not only websites, but the use of JavaScript also helps to create recreation games. The mixture of JavaScript and HTML5 also makes JavaScript popular in game creation.

Besides that JavaScript use to make Smartwatch Applications, Mobile Applications, Flying Robots, etc.

 

I hope, the article should help you to know the basic information about JavaScript.

Share your thoughts about JavaScript in the comment box.

Read Also:

C Language (Basics)

C++ Language (Basics)

Java Language (Basics)

PHP Language (Basics)

Python Language (Basics)

Ruby Language (Basics)

Swift Language (Basics)

HTML Language (Basics)

CSS Language (Basics)