What is Javascript?


You can’t get very far in tech these days without running into javascript. The good news is that javascript isn’t nearly as scary as it sounds, and it actually enables a lot of the cool things you probably already use on a daily basis. For example, when your Facebook timeline updates automatically or you type a few letters into Google’s search bar and the suggestions appear — that’s javascript in action.

Developed in Netscape, javascript is used to make web pages dynamic and interactive. It works in conjunction with hypertext markup language (HTML) and cascading style sheets (CSS). jQuery is a popular javascript library that helps developers build responsive websites and applications. Moreover, many of the world’s largest tech companies use javascript to enhance user experiences across their sites and mobile apps.

A multi-paradigm programming language, javascript is both object-oriented and functional. It has several features that make it a powerful programming tool, including a dynamic typing system, inlining, and a function call optimization process called Just-in-Time compilation. Its high-level language means it’s easy to read for human beings, and it’s been around in some form or another for decades.

When you run a javascript program, the code gets interpreted and executed on your computer. To do this, the engine converts the source code into bytecode. The engine then translates the bytecode into low-level machine code and executes it. This happens in parallel with the execution of the interpreted code, so it’s very fast and efficient.

The way it does this is called dynamic typing, which allows the JS engine to determine at runtime which data type a variable represents. It’s important to understand this because it affects how you write code. For instance, if you create a variable named “name”, the JS engine will consider it a string until you specifically assign it a different data type.

Another important feature of javascript is the ability to transform strings into numbers and numbers into strings. These conversions happen whenever you perform operations like concatenation, addition, subtraction, and division. This is also known as castling and uncastling. Using these functions is a key part of writing javascript efficiently, as it ensures that your code doesn’t run in unexpected ways.

In addition to these two features, javascript also supports a variety of other functions that allow you to manipulate objects in a very flexible manner. These include the eval function, which lets you execute statements provided as strings at runtime. This is useful when you want to add or subtract a large number of items quickly, or when you want to perform a series of calculations on a list of values.

While javascript can help you create great websites and apps, it can also negatively impact your site’s performance. Adding too many javascript scripts can cause your browser to take longer to download and display, especially on mobile devices. To avoid this, make sure your javascript is only used to add the functionality you need on a page.