What Is Javascript?

Created in 1995, javascript is an open-source scripting language that’s used to make web pages more interactive. It powers everything from the Facebook timeline that automatically updates on your screen to Google suggestions as you type. That’s because javascript is a client-side programming language, which means that it runs inside of your browser—and, in fact, is responsible for much of what makes websites and web apps functional.

Unlike many other programming languages, javascript is written in human-readable syntax. This is important because, even though computers can read js, they can’t actually understand it. Instead, a computer has to have an engine that can interpret the js code and turn it into machine-readable instructions.

There are multiple engines available for js. The most popular is the Google Engine, or GEC (which you can download for free and use in your own projects). The other main engines are Microsoft’s Babel and Apple’s JSEngine. While all of them have a similar underlying architecture, they each have slightly different features and quirks.

The key difference between them is how they handle variable declarations. The GEC treats const and var differently: var declares variables in the global scope, while constrained vars only occupy the region of the block where they are declared. This has some interesting consequences for variable shadowing. The GEC also does some interesting things with function parameters: it treats them as local variables rather than global parameters, and the function body is executed within the call stack.

This means that if you have a function in your program, you can call it just like you would any other local variable. The GEC is also smart enough to run your function recursively, which is pretty cool. Another great feature of the GEC is that it provides a name to every function, which can be useful in debugging.

Functions are the basic building blocks of javascript. They are an essential tool for writing scalable and modular code. There are several ways to create a function:

You can write your own functions from scratch, or you can use one of the many built-in functions in javascript. The most commonly used ones are map, list, filter, and zip. The list and map functions are especially helpful when dealing with large datasets.

JS uses a number of different data types. In addition to the standard string, int, float, and integer data types, there are boolean (True and False), symbol (used to create unique identifiers that won’t collide), and null.

One of the most important things to know about javascript is that it’s a dynamically typed language. This means that a computer, compiler, or browser cannot tell what kind of object is being created until it runs the code. It also means that if you’re writing a function, the engine will try to execute it as soon as you hit ‘Enter’.

To run a javascript command, open the website or page in which you want to test the code and then click More Tools > Developer Tools, or press Control+Shift+J (Windows) or Command+Option+J (Mac). This will open the console log, and you can start typing your command.