What is JavaScript? An Overview of JavaScript from A to Z

JavaScript - an extremely popular programming language in the development field today. It can be said that JavaScript, also known as JS, has become a widely used language in recent years. Quite a few frameworks have been introduced and written in this language. From frontend to backend, JS appears everywhere. The following information will help you understand more about this special language.

What is JavaScript?

JavaScript is a highly popular web programming language today. JavaScript is integrated and embedded into HTML to help make websites more dynamic. It also acts as part of a website, enabling Client-side Scripting from users as well as the server side (Nodejs) to create dynamic websites.

History of JavaScript Development

- Brendan Eich was the creator of JavaScript at Netscape, initially under the name Mocha. Later, Mocha was renamed LiveScript, and finally changed to JavaScript.

- In 1998, JavaScript was released with its latest version as ECMAScript 2, and in 1999, ECMAScript 3 was launched.

- In 2016, JavaScript adoption reached a record with up to 92% of websites using it, and it was also evaluated as an extremely important tool for developers.

How does JavaScript work?

Typically, JavaScript is embedded directly into a website or referenced via a .js or .javascript file. Because it is a Client-side language, the Script is downloaded to the client machine upon access.

Here, it is processed by the system. Therefore, you do not need to download it to the server machine and wait for processing to finish before returning the result to the client. Super deal 032023

What is JavaScript Used For?

Besides understanding what kind of language JavaScript is, knowing what it is used for is also very important. Grasping the purpose of this unique language will help you use it more easily in your work. Specifically:

- Changing HTML Content: One of the many HTML JavaScript methods is getElementById(). It is used to find an HTML element with id="demo" and to change the element's content (Internal HTML) to "Hello JavaScript".

- Changing HTML Attribute Values: In general, JavaScript can also be used to change attribute values. For example: changing the src (source) attribute of a tag.

Uses of JavaScriptUses of JavaScript

- Changing HTML Styles: This is a variation of modifying HTML attributes as mentioned above. For example: document.getElementById('demo').style.fontSize = '35px';

- Hiding HTML Elements: Another operation is that JavaScript can hide HTML elements. This can be accomplished by changing the display style of HTML elements.

- Displaying HTML Elements: A notable feature is that JavaScript can display hidden HTML elements. At the same time, this can also be achieved by altering the element's display style.

Pros and Cons of the JavaScript Programming Language

As a very popular programming language today, JavaScript possesses many outstanding advantages. However, alongside those strengths, the disadvantages of this programming language must also be noted.

Advantages

- The program is very easy to learn.

- JavaScript errors are easy to detect, thereby helping you fix bugs much more quickly.

- Web browsers can interpret it through HTML without needing a compiler.

- JS can run across multiple platforms and different web browsers.

- It is evaluated by experts as a lightweight programming language that is much faster than many other programming languages.

- JS can also be attached to certain elements or events of web pages.

- Websites that use JS gain interactivity as well as enhanced experiences for users.

- Users can also leverage JS to validate inputs instead of manual checks via database queries.

- A rich application interface with many components such as Drag and Drop, Sliders to deliver a Rich Interface to users.

- Enables client-side user operations while isolating clients from one another.

Disadvantages

Besides the aforementioned advantages, JavaScript still has its own drawbacks similar to other programming languages today. Specifically:

- JS Code Snippets are relatively large.

- JS is more vulnerable to exploitation by hackers and scammers.

- JS also lacks multithreading or multiprocessor capabilities.

- It can be used to execute malicious code on the user's computer.

- Different devices may execute JS differently, leading to inconsistency.

- For safety and security reasons, Client-Side JavaScript does not permit reading or writing files.

- JS is not supported when running on devices without a network connection.

Guide on How to Write a JavaScript Program

For developers, writing a JavaScript program is relatively easy. However, for beginners, writing a program in JS is still quite unfamiliar. Therefore, you can write a program using the following instructions:

Opening and Closing Tag Pairs

All JS code snippets are placed within the opening and closing tag pair . A simple, illustrative example:

Where to Place the Script Tag

In JS, we have 3 common ways to place the Script tag:

- Internal: Written within the current HTML file;

- External: Written to a separate JS file and then imported;

- Inline: Written directly inside HTML tags;

There are 3 commonly used ways to place the script tag as shown below:

With Internal, the Script tag is typically placed within the tag; however, you can also place it anywhere. The only requirement is that it must contain both the opening and closing tags . This way, you can place it in the head section of your existing HTML file.

With External, you write JavaScript code snippets in a new file. Then, you save this extension with the .js extension. Next, you use the Script tag to import the file. You do not need the closing tag because the .js extension is already present in the test.js file. Therefore, the browser will automatically recognize that this is a file containing JavaScript code.

With Inline, this method allows you to write JS code snippets directly inside HTML tags quickly.

Writing a JavaScript Program

Actually, writing a JavaScript program is relatively simple. Once you have learned about JavaScript and know what language JS is, next we will guide you on how to write a simple program as follows:

- Step 1: Create an index.html file anywhere on your computer, as long as it has the .html extension. Then, write a code snippet.

- Step 2: You can write the JavaScript program code executed when clicking the button with id="clickme".

With just these simple steps, you have completed writing your first JavaScript program.

Differences Between JavaScript and Other Programming Languages

The reason JavaScript has become the most popular programming language today is thanks to its inherent flexibility. In reality, many professional developers choose JS as their primary language while using other languages on the following list. So, what are the differences between JS and these languages?

If you view programming languages as building a house, HTML serves as the architectural blueprint of the house. CSS serves as the carpeting and walls to make the house more beautifully decorated.

JavaScript increases interactive elements within the house. For example, opening a door or turning on lights. You can still build a web page without JavaScript; however, the resulting risk is that your website might look like a product from 1995.

Guide on How to Embed JavaScript into a Website

To embed a JavaScript code snippet into a website, you simply need to attach the tag. Specifically:

How to embed JS into a websiteHow to embed JS into a website

A standard rule of thumb is that you should place JS within the tag of the website, unless you want JS to execute at a specific point in time or targeting a specific element of the webpage.

Additionally, you can also save JS code in a separate file. Whenever needed while using the web, you can load this file. Specifically, you can add JS directly into HTML or include JS in HTML via a separate, standalone file.

Tools Used for JavaScript Development

IDE is the acronym for Integrated Development Environment. This is an environment integrated with multiple tools and utilities. An IDE is regarded as a dedicated environment for developers when working with JS. Currently, widely used IDEs include:

Tools for JS development Tools for JS development

- Notepad++ tool.

- Visual Studio tool.

- PHP Designer tool.

- Dreamweaver tool.

- Sublime Text tool.

Besides these, you can also use several highly rated JS editing tools such as:

- Microsoft FrontPage tool.

- Macromedia Dreamweaver MX tool.

- Macromedia Homesite 5 tool.

Frequently Asked Questions

Before using JavaScript, you will certainly have many questions and concerns. To help resolve these inquiries, we have compiled several key questions below:

What is a script tag?

The Script tag is an element used to declare to the web browser that the content inside the file is a snippet of JS code.

What is Type = text/javascript?

When you declare a Script tag, the attribute type="text/javascript" appears. This parameter is used primarily to declare the media type for the data contained within the script tag. The system will default to text/javascript if you leave it undeclared.

Can JavaScript be used for backend?

Theoretically, JS is a Client-side language, so you cannot perform server-side operations with standard browser JS. However, when your server has NodeJS installed, the server side can use the JS programming language for development. This is because NodeJS runs on JavaScript.

Should you learn JavaScript?

If you want to pursue web development or mobile app development, you should learn JavaScript. Of course, you should not only learn JavaScript alone, but also acquire knowledge about JS frameworks to support your career.