What Is JavaScript?
If you’re a web developer, chances are you’ve heard of javascript. It’s a programming language that allows you to add interactivity and animation to websites, and it can make sites responsive to user input. It’s also used in some apps and games, so you might have seen it in action without even realizing it.
Unlike traditional languages that are compiled before being executed, javascript is interpreted when it’s run, which means that the code is actually running as soon as it passes into the engine. When a snippet of javascript enters the engine, it gets parsed and turned into a data structure called an abstract syntax tree. This is then translated into machine code using something called Just-In-Time compilation. Once this is done, the code can then be executed, which is how your browser handles things like scrolling in a page or adding an event listener to a button click.
The fact that it’s so easy to use makes it an important tool for developers, and as a result, javascript is the most widely-used language on the web. All modern browsers have built-in engines that can interpret javascript, so you don’t need to install any additional software to write a script. This also makes it easy to test, since you can just open up your browser and see what happens.
What Is JavaScript Used For?
As a client-side programming language, javascript is used for front end web development. That means that it’s mostly used to create interactive elements on websites and apps, like a Twitter feed that automatically refreshes or an online form that prepares the information you enter and submits it to a database. It can also be used to access APIs, or Application Programming Interfaces, which are functions in software that are left open so other developers can access and use them with their own programs.
One of the most interesting things about javascript is that it’s a dynamic language, which means that it can work with a dynamic web page. The DOM (document object model) of a website is a hierarchical structure that represents the HTML elements on a page, and JavaScript can manipulate this in real time to give a webpage more life and interaction. This is how a website can change to match a user’s action, like showing different search results after they start typing in the bar.
For example, let’s say you wanted to get a list of all the buttons on a website and add an event listener to them for when they are clicked. This can be done with a simple loop in javascript, as shown below: