What is Javascript Essentials?

JavaScript is a programming language commonly used in web development. It was originally developed by Netscape as a means to add dynamic and interactive elements to websites.

It is supported and implemented by most modern browsers today, including Firefox, Internet Explorer, Safari, and Chrome.

For example, a JavaScript function may check a web form before it is submitted to make sure all the required fields have been filled out.

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Not only that; there are also functions that can be performed when you move your mouse over an element or resize your browser window! This animation shows how much work JavaScript can do:

JavaScript was created to make the web more dynamic. HTML, or Hypertext Markup Language, is a markup language that sets up the structure of a website. For example, it defines what a paragraph looks like, how content can be ordered, and so on.

CSS, or Cascading Style Sheets, tells the browser how to display this code in terms of color schemes and fonts. With HTML and CSS alone, websites are extremely dull—but with JavaScript added to the mix, they come alive!

But what are some real-life applications for these technologies? A car manufacturer uses them to create an interactive experience where visitors can customize their dream car (using HTML and CSS), and the website then automatically calculates the cost (using JavaScript).

More famously, ” Google Maps ” uses JavaScript to display interactive maps. Using an external API that makes use of JavaScript, users can zoom in on different areas around the world, move around using the mouse, and see satellite images of specific locations.

This is all processed by a computer server at Google HQ—the client itself just has an interface where they can interact with it.

JavaScript isn’t just used for adding dynamic functionality to websites either! For example, wouldn’t be possible without JavaScript to control the complicated process of communicating with a server.

The result would be an application that is unable to determine your location, crash frequently, and so on!

Why Javascript is used?

JavaScript has many uses in web development. It can be used alongside HTML and CSS to help websites look better and function more efficiently.

JavaScript can also be used on its own without any other technologies using APIs, or Application Programming Interfaces.

These are sets of rules that allow applications to communicate with each other. For example, there is a standard set of code for maps that allows them to talk to servers about location coordinates—so you don’t have to write all of this yourself from scratch every time! There’s nothing stopping websites from creating their own internal JavaScript APIs either…

Basically, HTML and CSS set out the structure and style of a website, while JavaScript adds dynamic functionality. This allows websites to be much more interactive than they could be otherwise!

JavaScript is a programming language commonly used in web development. It was originally developed by Netscape as a means to add dynamic and interactive elements to websites.

JavaScript can be included in an HTML file (known as client-side scripting) or it can exist on its own in the form of files called scripts, which are executed by the JavaScript engine of the user’s web browser when opened (known as server-side scripting).

For example, a JavaScript function may check a web form before it is submitted to make sure all the required fields have been filled out.

Once written, JavaScript code exists within specific containers known as contexts. A context defines where the code is located and what privileges it has access to perform actions on objects contained within that context.

These contexts include the Window object, governed by the Window context, and Document objects associated with webpages, governed by the Document context.

For example, JavaScript in a webpage may only access items (elements) that exist within that webpage’s context. However, JavaScript in an iFrame may be able to access elements in its own context as well as elements in the parent webpage’s context.

The location of JavaScript within a webpage determines which other HTML tags and attributes it has access to; for example, if JavaScript exists in an embedded <script> tag, it will not have access to any input or form data because they reside in different contexts.

Contexts also determine what kind of events specific code can react to. For example, Event Listeners in the Window context can only react to events related to window objects, whereas Event Listeners in the Document context may also be able to detect changes made within that webpage’s body tag.

JavaScript has gained popularity because it makes web pages more dynamic and interactive. It allows users to continuously interact with websites without having to refresh pages every time they input data or choose an option.

For example, JavaScript can be placed into web forms (specifically javascript: pseudo-protocols) so that when a user submits the form information is sent via JavaScript rather than HTML; this could be done through Ajax requests.

Because JavaScript can access any element in its containing context, it is possible for one piece of code to communicate with another; for example, it can request data from a database and then display that data on the webpage without having to reload the page.

JavaScript also allows developers to expand their abilities by creating custom libraries containing code blocks; these can be included in webpages as needed for future use.

JavaScript is commonly implemented within web browsers through a built-in JavaScript engine (also known as JavaScript interpreters) which is responsible for executing all scripts and providing access to any HTML elements contained within the webpage’s context.

Originally, JavaScript was supported solely in Netscape Navigator but has since been added to other popular browsers such as Mozilla Firefox, Google Chrome, Internet Explorer, Opera, Safari, Yandex Browser, and Microsoft Edge.

The version of JavaScript supported across all major browsers is ECMAScript (version 5.1 as of February 2015), but other versions are supported in some contexts; for example, Internet Explorer 9 supports ECMAScript 3.

Most modern JavaScript engines support the JSON data format and allow developers to directly work with APIs that use JSON output; this makes it easier to send API requests and receive API responses without having to convert between formats.

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