What is WebAssembly?
WebAssembly technology is a library for compiling application code into binary assembly code that can be run in or outside the browser. Unlike Flash technology (which may be phased out in the near future), WebAssembly support is built into browsers as well as JavaScript support, so you don’t need to install any plugins for it to work.

Let’s try to understand what WebAssembly is by the following analogy. Any of your desktop programs (for example, the same Firefox browser) are strings consisting only of ones and zeros that the computer understands. This format is called binary. Binary programs are created by compiling applications written by programmers in one of the programming languages. But since neither your nor any other PC understands programming languages, the program has to be compiled into a binary format – into zeros and ones.

WebAssembler is a binary assembly language, also consisting of zeros and ones, readable by any computer. When the computer sees the WebAssembly code, it might say, “Great, I understand this code. This program”. Thus, the computer does not need additional resources to compile this code, which will affect the high performance of the application.

Can WebAssembly be compared to JavaScript?
Today, most web applications are written in JavaScript (JavaScript) language, the code of which runs in almost any browser. JavaScript has been used for many years to write fast web applications. But in the end, JavaScript is an interpreted language whose program code the computer must check and execute line by line. This can lead to some complications, especially on mobile devices.

If you’ve ever wondered why a web page works great on a PC, but at the same time is slow on a mobile device with the same Wi-Fi connection, then this is probably the reason. There is a huge difference between the PC and mobile ecosystems. Although the JavaScript code is optimized to run quickly in a web browser before running, the mobile device might not be powerful enough.

The following comparison can be made. Compiled binary code is perceived by a computer device as a native language. The interpreted code is like a foreign one. To understand a foreign language, the device has to work harder.