What is ES6 and difference between ES6 and javascript?

Answer 1

ES6 is ECMAScript otherwise known as Javascript.
No difference between ES6 and Javascript.
ES6 is the latest version of Javascript.

Answer 2

the ES6 stand for ECMAScript v6. ECMAScript where people most popular say it with JavaScript. Class, new variable, modules added, etc.
Most of modern browsers has support ES6 now.
Commontly used JavaScript is ES v5.