This is an object-based scripting language which is cross-platform and lightweight language.
V8 – in Chrome and Opera.SpiderMonkey – in Firefox.
There are other codenames like “Trident” and “Chakra” for various versions of IE, “Nitro” and “SquirrelFish” for Safari, “ChakraCore” for Microsoft Edge, etc. The terms above are good to recollect because they’re utilize in developer articles on the web . We’ll use them too. As an example , if “ V8 supports a feature X ”, then it probably works in Opera and Chrome.
How do engines work?
Engines are complicate. But the fundamentals are easy.
The engine (embedded if it is a browser) reads (“parses”) the script.
Then it convert the script to the machine language.And then the machine language runs, pretty fast.
The engine applies optimizations at each step of the tactic . It even watches the compiled script because it runs, analyzes the info that flows through it, and further optimizes the machine language supported that knowledge.