Javascript: Web Browsers Engines

What are the Javascript Engines (browsers) out there? and Who is using what?


IE and Edge uses the Chakra(JScript) engine. 
"JScript is the Microsoft implementation of the ECMA 262 language specification (ECMAScript Edition 3)".


"Chrome uses the V8 Engine. V8 is Google's open source JavaScript engine".


Firefox uses SpiderMonkey (Tracemonkey). "SpiderMonkey is Mozilla's JavaScript engine written in C/C++. It is used in various Mozilla products, including Firefox, and is available under MPL/GPL/LGPL tri-license."


"The Nitro JavaScript engine is an advanced bytecode JavaScript engine that makes web browsing even faster, and it’s what powers Safari on the Mac, PCs, and iOS devices."


Opera uses an Javascript engine called carakan (futhark old version).