JavaScript Introduction

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The current essay is devoted to the basic principles and introduction of JavaScript. This language no longer needs to be introduced since it has become integral to any web development. Everybody knows that JavaScript is not that easy to IGNORE. Read this article if you want to understand the core principles of Javascript from getting to know its key structure. And also you will know how it helps create MOVABLE, MORE INTERESTING, and TASTIC content.

For all the wannabe programmers out there, or if you want to improve your web programming prowess. This article will form a solid ground in Javascript targeting the relevant notions and ideas needed for web app development.

JavaScript Introduction

In the following section, you will understand what JavaScript is, so let’s move on to it.

What JavaScript Means

JavaScript is an interpreted, high-level programming that is used to build dynamic and interactive features on web pages.

Web browsers and page JavaScript web-interactive content and features. Such as multimedia, games, dynamic content updates, and validation, are made possible with this technology.

JavaScript is indispensable both on the client side and server side. It is on the client side that the script is executed in the browser. It enables interaction with the web page thus no page has to be loaded.

This therefore makes the websites easier and more pleasant to use. There also exists server-side scripting in which scripts are written in JavaScript using environments like Node.js to operate the server, databases, and web pages.

This makes JavaScript a tool that can be employed in the development process at both the front and the backend stages since both the front-end and back-end interphase with the application.

In the next section, you will take an overview of the JavaScript history.

JavaScript History

Before getting started in the history overview, JavaScript is only one language. And there is no language else to do its job, especially in the front-end stage. That’s all.

Before JavaScript, web pages were only static pages and were lacking for dynamic procedures. So they decided to develop a scripting language for the Netscape Navigator.

The Netscape team was thinking of collaborating with Sun Microsystems to use their Java Programming language with the Netscape tool. But that was failed for some unknown reasons.

They decided to hire someone else to do this task, he called Brendan Eich, and let me say, that was the greatest decision ever made in history.

Brendan Eich started the task and generated the first version of the scripting language in 1995 and embedded it into the Netscape version 2.

Live Script

The language syntaxes were similar to syntaxes of the Java programming language, and its interpreter was called “LiveScript”.

Eich was thinking of The name for his new scripting language. At this time Java was in hot demand and its popularity was officially spread. So he named his new scripting language with JavaScript name. And that was for a marketing ploy.

JScript

Microsoft takes over to generate its new Internet Explorer browser and that start a new war for browsers, against Netscape Navigator company.

Microsoft team released their scripting language in 1996 to embed it with Internet Explorer, they named it “JScript”.

This version supported HTML markups and CSS.

During this period, most of the developers weren’t able to develop their websites in two browsers to have the same design in both. It was a big change in the design and structures of two both.

So, this point leads Netscape and Microsoft to create other attractive sentences and slogans to do a ploy marketing for each other.

Netscape used the slogan “best viewed in Netscape”, while Microsoft used “best viewed in Internet Explorer”.

ECMA Script

To finish the slogan war. The Netscape company created a standard specification for the first ECMAScript language, and that was in 1997.

During several years, they released many versions of the ECMAScript language each year with a new version starting in 1998 and ending in 2000 with the name ECMAScript 4.

But Microsoft was not standing idly because its Internet Explorer was in spread. They reached 95% of the market.

That means Microsoft JScript became the standard specification for the client side of the web application.

In 2000 the ECMAScript was stopped with version 4. Because JScript became more popular than ECMAScript, Microsoft won.

ECMA Script and Macromedia

In 2004, Mozilla continued the challenge and released their new browser called “Firefox”, they improved this browser with ECMAScript 4 of the Netscape Navigator and did many other features according to the ECMA International standard.

This browser started to spread, and it became challenging for Google company and Microsoft.

V8 JavaScript Engine

In 2008 Google started a new challenge and released the Google Chrome browser with its v8 JavaScript engine. This browser was faster than Google Chrome competitors. Because they were dependent on just-in-time compilation.

In the next section, we will focus on the V8 JavaScript engine of the Chrome browser. Let’s dive right in.

How the V8 JavaScript Engine Works

V8 engine is a Google project which is an open source created to do a high performance for the JavaScript programming language.

The V8 engine is written in C++ programming language and implemented with two phases which are ECMAScript and WebAssembly.

Additionally, the v8 engine works with major operating systems such as Windows, macOS, Linux, and so many others.

Anyway, the mission of the V8 JavaScript engine is to translate the source code into binary bits (the machine code). And here, we are going to cover these phases. But before getting started, you have to know the difference between compiler and Interpreter.

The Lexical Tokens

The first step is receiving the source code from the server. Then it starts to analyze it according to some instructions in the lexical analysis and then generates a string containing the sequence of Lexical Tokens. This phase is also called a scanner.

The Parser

The parser receives the sequence of tokens and generates the Abstract Syntax Tree (AST) which represents those tokens in a big structure.

The Interpreter

Once it receives the AST, the Ignition interpreter starts to generate the bytecode and that was produced from the AST.

Then it sends bytecodes to TurboFan, and here TurboFan converts these bytecodes into binary bits which is the machine code.

On the other hand, the V8 engine has another thing called a Just-In-Time compiler to convert ECMAScript into native machine code before the execution.

The compiled code is another optimization or (re-optimized) to be a highly optimized binary bit or machine code.

If incorrect things are happening during this stage. It de-optimizes it and returns it to the interpreter to re-evaluate.

That was an overview of the V8 JavaScript engine work from the top. In next section, you will learn more about JavaScript Capabilities and Limitations.

Capabilities and Limitations of In-Browser JavaScript

Capabilities of In-Browser JavaScript

  • Security Concerns: The Same-Origin Policy as well as other safety measures prohibits in-browser JavaScript from accessing sensitive information without authorization. However, it is still vulnerable to cross-site scripting (XSS) attacks if not handled properly.
  • Browser Dependency: There is a strong reliance on the Browser’s Database Engine when executing JavaScript. This may bring up issues in terms of certain behaviors, or performance in different browsers, although most if not all circumvent such issues with modern browsers today.
  • Performance Limitations: As earlier stated, JavaScript comes in a single thread, even though Web Workers allow some concurrency, so performance issues are inevitable in complex applications. Heavy processing activities can also affect the responsiveness of the application and lead to stutter.
  • Limited File Access: Since the JavaScript code is executed within the browser, any scripts have no or very little access to the file system, chiefly because of security reasons. It can only handle files that are uploaded by the user through file inputs.
  • Dependence on User Settings: JavaScript can be turned off by the users of the website where certain functions are implemented, and this may constrain the implementation of some features of the webpage. In such circumstances, developers should offer fallback measures.

Limitations of In-Browser JavaScript

  • Safety Issues: The browser restriction on JavaScript, imposing the Same Origin Policy and other security measures, is to limit the exposure of sensitive information. That said, if not well managed, it still poses a risk of cross-site scripting (XSS) threats.
  • Browser Dependency: The execution of JavaScript is dependent on the JavaScript engine built in the browser. This creates an inconsistency in the behavior or the performance of the different browsers, although quite a number of these issues have been addressed in modern browsers.
  • Performance Bottlenecks: JavaScript is a single-threaded application (although Web Workers can provide some multi-threaded capabilities) which spells doom for most complex applications. High-end processes will usually thumb down the user interface and freeze the entire application.
  • Limited File System Access: A JavaScript running in the web browser has substantially restricted access to the file system under normal circumstances and mainly for security purposes. It can only reach files that the user physically selects through file input elements.
  • User Configurations Restriction: Certain aspects of JavaScript can be turned off by a user in their web browser which could limit some functionalities in the website. This is an eventuality that designers have to consider and make provision for.
  • No Direct Access to Operating System Features: In-browser JavaScript cannot communicate with the underlying operating system as is the case with server-side languages or applications. This also makes it difficult to perform operations such as managing files, using hardware peripherals, and using the network stack.

In the next section, I am going to write a program with JavaScript. Only to show a dialog box with – a “Hello World !” message.

Write your First Program with JavaScript

Firstly, you have to install an editor to allow you to write the JavaScript code. And then copy the below code. Then open it in the browser.

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

The result would be a popup box containing the – “Hello World !” message.

FAQs

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

JavaScript is a high-level, multi-paradigm programming language that is mainly used as an interpreter to add dynamic features to web pages. As a result, it is important for the contemporary web, allowing the enhancement of user experience for all web pages.

How does JavaScript make web pages dynamic and interactive?

With JavaScript, you can update and change the content of a web page without having to reload it. It provides features that support multimedia, games, and other stuff as well as help through dynamic content update mechanisms and real-time form validation — cases that make our webpages more interactive for the user.

Can JavaScript be used both on the client side and server-side?

JavaScript can run on the client side, in your browser, to manage user interactions with a web page and also on the server using environments like NodeJS backend code using JS, databases, and server operations.

What is the history behind the development of JavaScript?

JavaScript was created in 1995 by Brendan Eich to add interactivity and dynamic behavior to the Netscape Navigator browser. Originally named LiveScript, it was created to inject interactivity into static web pages. And eventually, it has emerged as the common language for web scripting.

Who created JavaScript, and when was it first introduced?

JavaScript was developed by Brendan Eich in 1995, inside Netscape. It became a part of Netscape Navigator 2.0 for the first time.

Why was JavaScript initially called LiveScript?

JavaScript was designed as LiveScript when it had only a few days of existence, the syntax resembled Java. In fact, they changed the name to recognize this and how popular Java was as a marketing ploy.

What is the difference between JavaScript and JScript?

JScript is Microsoft’s implementation of JavaScript, developed to support the Internet Explorer Web browser. Though closely related in its functionality, JScript and JavaScript originated from separate companies that created challenges with the compatibility of the technology across browsers during this early formative age of the web.

JavaScript conforms to ECMAScript, a standardized specification for scripting languages. The code was formerly standardized by the European Computer Manufacturers Association (ECMA) to ensure that it does not invalidate on different web browsers and platforms.

How does the V8 JavaScript engine improve JavaScript performance?

Google created the V8 engine which is meant to compile JavaScript into machine code using JIT (Just-In-Time) compilation, This adds performance lift when running JavaScript. That means JavaScript will perform faster and more efficiently, particularly in modern web browsers such as Google Chrome.

What are the key phases of the V8 JavaScript engine’s execution process?

V8 engine processes JavaScript in the following way:

  • Lexical analysis – conversion of source code to tokens.
  • Parsing – generation of an abstract syntax tree.
  • Interpreting – conversion of AST to bytecode.
  • Compiling – conversion of bytecode to machine code for execution.
  • Optimization – making of machine code for performance.

What are the capabilities of in-browser JavaScript?

  • Interactive and dynamic content can be pushed to the users with JavaScript in their browsers.
  • Validate forms, modify content on the fly without ever having another page request/reload/refresh your very sidebar, or just load multimedia files/images for immediate preview — and execute any kind of script client-side.

What are the limitations of in-browser JavaScript?

Disadvantages include security risks (specifically at risk for XSS attacks), browser capabilities restriction (performance may vary between browsers) a performance tuning problem due to the nature of JavaScript being single-threaded, limited file system access and user-choice based mechanisms(JavaScript can be disabled by users).

How can JavaScript’s performance be affected by complex applications?

Because JavaScript is single-threaded, intensive apps can make performance slow or cause stuttering and even the UI freezes in big processing tasks. Web Workers can give us some level of concurrency but still, they are limited by performance problems.

Is it possible for users to disable JavaScript in their browsers? If so, what should developers consider?

Yes, JavaScript can be turned off in a browser and it might break some features on the site. If someone turns off JavaScript or has an issue where the script does not load, devs should be thinking about fallback methods.

Wrapping Up

This introduction explains JavaScript in great detail for beginners as to why it is regarded as a basic tool in web design. It mentions that JavaScript is a programming language that enables web pages to be more than static documents and interactive on both the client and server side.

This introduction has analyzed in detail how javascript has evolved over the years from how Brendan like invented it for Netscape Navigator until the time it became necessary in the web development phenomena. The comparison between JavaScript and JS which is a simpler version created by Microsoft for use on the Windows operating system among other related issues on the subsequent browser wars is presented.

V8 JavaScript Engine created by Google as part of Chrome is a suitable instrument that is used for code compiling known as Just In Time Compilation of Javascript Codes to the Machine Code. The article also describes the so-called in-browser Java Script, covering its advantages and disadvantages, including such issues as safety, browser, performance, and access to files.

To conclude the article, a simple example is presented, showing the steps to make a program in Java Script which prints “Hello World!” making it easy for the audience to learn the process of writing, saving, and executing the basics of scripting.

Thank you for reading. Happy Coding!

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