How Does Javascript Work?
Whether you’re a beginner who’s just started exploring web development or an experienced developer, you probably have some familiarity with the javascript language. You may have even used it for creating your website’s front-end features. But have you ever wondered how javascript really works? This article will take you through the steps that are taken by the javascript engine and the browser in order to produce the output you see on your screen.
javascript is one of the most widely used programming languages in the world, and it’s often seen as the language that allows web developers to create dynamic web pages that are based on the Document Object Model (DOM) standard. It’s a relatively lightweight, minimalist programming language with minimal data types and a syntax that can be easily learned by most programmers.
It can be used for client side & server side scripting, but it’s most commonly used for web applications. It’s event-driven, allowing it to respond to keystrokes and mouse clicks, and it has access to the DOM, enabling it to manipulate the layout and style of web pages. It’s also single-threaded, allowing it to execute a sequence of tasks sequentially and handle asynchronous operations with a callback queue.
The first thing you need to understand is that javascript runs inside a host environment, which in most cases is the browser. This means that in order to run your javascript code, you must have a modern web browser installed on your computer. Thankfully, most of the popular web browsers today support javascript and provide an interface to enter javascript code into a web page. This interface is usually referred to as the Web Console and can be found in the Tools menu of most browsers.
Once you’ve got a web browser with the javascript plugin enabled, you can start writing your own code. You can do this in the JS Console, in any text editor, or using sites like CodePen that supply all the software you need to get started.
When you enter a piece of javascript into the console or an editor, it is parsed and translated to byte code. The byte code is then passed to the processor which understands binary, 0’s and 1’s. The processor then uses that byte code to run the javascript function.
As the js code is running, a global execution context, or GEC, is being created and pushed to the call stack. Each time a function is called, its stack frame is added to the call stack. Once the function returns, its stack frame is popped off the stack and execution resumes at the return address.
There are some nuances to the javascript runtime, which is why it’s important for programmers to understand how it functions. In particular, javascript has a limited number of data types and a prototype-based object model that provides dynamic inheritance. These characteristics can sometimes cause bugs in javascript that aren’t present in other languages with more robust data types and object models.