Understanding the Basics of JavaScript

A key component of standard web technologies, javascript is used to add dynamic elements in web development. It can track user input and manipulate the Document Object Model, making it a very flexible language for web applications. The language is also “event-driven” allowing it to respond to events such as clicks and keyboard input, which can be helpful in creating more interactive features like image sliders and games.

A high-level, single-threaded, garbage-collected, interpreted (or just-in-time compiled), prototype-based, multi-paradigm programming language with a non-blocking event loop.

JavaScript is a complex language and it may take years of experience to fully understand its many features and how they work together. However, understanding some of the basic concepts can help you be more productive with the language.

Essentially, javascript is run inside an execution environment called the browser tab. It takes in raw materials (the code) and outputs a finished product (the web page). This process is very similar to a factory that takes in raw material (raw code) and produces a finished product (web page).

Each function call creates a new execution context, which contains all of the information needed to execute that function. Each function is executed in the order that they are declared, and the first one to be called will be executed first. The rest will be queued up and executed in the order that they were called. This process is called the call stack. Each execution context has a heap, which is where objects are stored, and a call stack, where variables referencing these objects are stored.

There are a number of keywords that are important to understand, including let, const, and var. Let allows you to declare block-level variables that will be available throughout the scope of the block, const allows you to declare constants that will not change, and var lets you declare variable values that can be changed at any time. There are also a number of operators, such as equals and greater-than/less-than. These operate on boolean values and have their equivalents in other languages, such as Python, Perl, and Bash.

One of the most important aspects of javascript is its ability to interact with the DOM, which is the browser’s internal representation of the web page. This enables the language to dynamically change a webpage, and is especially useful for creating things like image sliders and slideshows. It can be used to change fonts, images, text, and form fields on a webpage. It is also very popular for interacting with user input, displaying different content based on the user’s actions. For example, if they click on a particular image in a carousel, the next image will display. This feature is possible because of the events that are triggered when a user interacts with a website. These are sent to the server, and can then trigger a response such as advancing to the next slide or removing an image from the carousel. This functionality is made possible by javascript’s event-driven nature and Ajax.