javascript is the third element of web development, after HTML and CSS. It’s what makes websites dynamic, adding things like drop-down menus that appear when you click on a page element or the ability to submit a form with one click of a button. JAVASCRIPT is also what lets you use advanced UI elements, like autocomplete, on forms, and it provides the foundation for APIs, which allow you to connect to a server, grab data and then return it back to a user.

In order to create these kinds of dynamic features, javascript needs to work with the browser. When you load a website, the browser parses the HTML and then grabs any files and inline code that are linked to it (like images). Once that’s done, the browser will run your javascript code.

Your javascript code is executed inside of an execution context, which the engine creates. The engine will assign memory to your variables and then execute each line of your code. When the function finishes, it will destroy its execution context. Then the next line of your code will start to be processed, and so on. This process is referred to as “inlining” because your code is being run in a new context for each function call.

The engine also offloads long-running tasks from the single js thread and enqueues a callback function to be executed by the main JS thread when the task is completed. This is a feature called non-blocking. The engine and the DOM will both wait for synchronous code to be finished before continuing to execute more tasks.

Another cool feature of javascript is that it’s a high-level programming language. This means that it doesn’t have direct interaction with the bare metal hardware of your computer, instead using memory management techniques like garbage collection. This means that your code will run faster than low-level languages that have to interact with the hardware directly.

JavaScript is used in some of the world’s most popular websites and is an important part of what makes the web so dynamic. It’s used in social media apps, online gaming and more. The fact that it’s so widely supported in web browsers makes it the go-to scripting language for web developers.

Despite its complexity, javascript has a reputation for being easy to learn and understand. It has a simple structure and syntax, and errors are easy to spot. It’s also fast, executing within the web browser without connecting to a server or having to be compiled before running. It also offers a wide variety of functions and libraries to make web apps and sites more functional and user-friendly. For example, you can use javascript to add social media features to your site or to suggest search terms as you’re typing. This is because a program on the server analyzes your words and runs algorithms to predict what you want to see. It then communicates that information to the JavaScript on your browser so that it can anticipate what you’re looking for before you finish typing.