chrome java script engine is called v8 , u can run java script codes 
without the need for external package
Node js provides the compile package and run time development envierment  
based on v8 engine  to excute javascript outside of a browser   	
..to build highly scalable services and fast
node commands 
*node --version 
*node app.js
*jshint app.js

EventEmitter class
emitter object
emitter . emit
emitter listner .on

Express is node js framework