What is CoffeeScript?
CoffeeScript is an attempt to expose the good parts of JavaScript in a simple way. The golden rule of CoffeeScript is: "It's just JavaScript". The code compiles one-to-one into the equivalent JS, and there is no interpretation at runtime.
CoffeeScript is a little language that compiles into JavaScript. Underneath that awkward Java-esque patina, JavaScript has always had a gorgeous heart. CoffeeScript is an attempt to expose the good parts of JavaScript in a simple way.
CoffeeScript is a program that takes some text you write using a special set of rules and transforms it into some other text, which happens to be a JavaScript program. It is often described as a programming language that "compiles" to JavaScript much as other programming languages compile to assembler or JVM byte codes.
Video for Introduction about CoffeeScript
