How to check if js code is running on node server or on the client

How to check if js code is running on node server or on the client

References

Reference NO 1

http://stackoverflow.com/questions/13644303/how-to-check-if-js-code-is-running-on-node-server-or-on-the-client

Reference NO 2

http://timetler.com/2012/10/13/environment-detection-in-javascript/

Reference NO 3

http://sebastianpatten.wordpress.com/2011/12/13/node-sharing-javascript-code-between-client-and-server/

Reference NO 4

http://howtonode.org/

Reference NO 5

http://engineering.linkedin.com/nodejs/blazing-fast-nodejs-10-performance-tips-linkedin-mobile

Reference NO 6

http://brianstoner.com/blog/testing-in-nodejs-with-mocha/

Reference NO 7

https://github.com/sockjs/sockjs-client

Reference NO 8

https://www.twilio.com/blog/2013/04/introduction-to-twilio-client-with-node-js.html