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What Is JavaScript?

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JavaScript is one of the most popular programming languages on the Internet. It is used to build interactive, dynamic user interfaces for websites and mobile apps. It also has a variety of uses in back-end web development.

JS is supported in multiple operating systems, including Windows and macOS, and has a large number of popular frameworks and libraries for developers to use. It is also a widely used language for data science and machine learning applications.

It is a high-level programming language that provides a great abstraction over the hardware and operating system of a computer. This makes it easier to program and maintain.

In a typical webpage, JavaScript is loaded and executed after HTML and CSS files have been parsed and the Document Object Model (DOM) has been created. The DOM contains information about the web page’s contents, including images and styles.

For example, if you were to write an information form that asks for the user’s age, you would need to include several JavaScript elements to validate the input. These elements include code that checks if the input is valid and an action button to submit the form.

To build these elements, you would create an array of references to the buttons on the page. Then, you would loop through the list and add a click event listener to each one.

This code would then run when the user clicked on any of the buttons on the page. It would then update the page’s content based on the value of the variable that had been set for each of the buttons.

The JavaScript code is then interpreted, which means that it is read and executed by the browser’s JavaScript engine. The JavaScript engine then executes the code line by line, assigning memory to each of the variables and functions that were defined in the code.

During this process, JavaScript will store ‘undefined’ for the variable and the value of ‘2’ for the function. Once it has finished, it will destroy its execution context. This will then free up memory that it had allocated for the variable ‘num’ and the square2 function.

JavaScript’s high-level language design makes it easy to write and debug, which is a big benefit when working with complex applications that require complex interactions. Moreover, it can be easily extended to add new features, such as image transformations and event loops.

Another benefit of the high-level language is that it can be compiled into native machine code for faster execution. However, this requires the use of a compiler and can be time-consuming.

It can also be run in the background, which is a big advantage when a website is being hosted on a server. This allows a web server to handle tasks like database management and security updates without disrupting users’ experience.

As a result, JavaScript is incredibly versatile and widely used. It is used in every industry to build all kinds of applications, from websites to mobile apps and back-end web development.