Javascript.info

“Javascript.info” is a comprehensive online resource for learning JavaScript, covering a wide range of topics from basic to advanced concepts. The content is structured in a beginner-friendly manner, making it accessible for learners of all levels. The website provides detailed explanations, code examples, and interactive exercises to help readers grasp JavaScript fundamentals and enhance their programming skills. With a focus on practical applications and real-world scenarios, “Javascript.info” aims to equip individuals with the knowledge and tools needed to become proficient in JavaScript development.

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Arrays

Javascript.info

Objects allow you to store keyed collections of values. That’s fine. But quite often we find that we need an ordered collection , where we have a 1st, a 2nd, a 3rd element and so on. For example, we n...

Comparisons

Javascript.info

We know many comparison operators from maths. In JavaScript they are written like this: Greater/less than: a b , a < b . Greater/less than or equals: a = b , a <= b . Equals: a == b , please note the ...

Class checking: "instanceof"

Javascript.info

The instanceof operator allows to check whether an object belongs to a certain class. It also takes inheritance into account. Such a check may be necessary in many cases. For example, it can be used f...

Code structure

Javascript.info

The first thing we’ll study is the building blocks of code. Statements Statements are syntax constructs and commands that perform actions. We’ve already seen a statement, alert('Hello, world!') , whic...

Developer console

Javascript.info

Code is prone to errors. You will quite likely make errors… Oh, what am I talking about? You are absolutely going to make errors, at least if you’re a human, not a robot . But in the browser, users do...

Function binding

Javascript.info

When passing object methods as callbacks, for instance to setTimeout , there’s a known problem: “losing this ”. In this chapter we’ll see the ways to fix it. Losing “this” We’ve already seen examples ...

Error handling, "try...catch"

Javascript.info

No matter how great we are at programming, sometimes our scripts have errors. They may occur because of our mistakes, an unexpected user input, an erroneous server response, and for a thousand other r...

Function object, NFE

Javascript.info

As we already know, a function in JavaScript is a value. Every value in JavaScript has a type. What type is a function? In JavaScript, functions are objects. A good way to imagine functions is as call...

Async/await

Javascript.info

There’s a special syntax to work with promises in a more comfortable fashion, called “async/await”. It’s surprisingly easy to understand and use. Async functions Let’s start with the async keyword. It...

Prototype methods, objects without proto

Javascript.info

In the first chapter of this section, we mentioned that there are modern methods to setup a prototype. Setting or reading the prototype with obj.__proto__ is considered outdated and somewhat deprecate...

Polyfills and transpilers

Javascript.info

The JavaScript language steadily evolves. New proposals to the language appear regularly, they are analyzed and, if considered worthy, are appended to the list at https://tc39.github.io/ecma262/ and t...

Arrow functions revisited

Javascript.info

Let’s revisit arrow functions. Arrow functions are not just a “shorthand” for writing small stuff. They have some very specific and useful features. JavaScript is full of situations where we need to w...