Edit in JSFiddle

//global variable siteName - accessible everywhere!
var siteName = "EasyProgramming";
console.log('siteName outside is ' + siteName);

//function - siteName is still accessible, but topic is only accessible from within the function
(function outputName()
	console.log('siteName in the function is ' + siteName);
  var topic = "JavaScript";
  console.log('Topic in the function is ' + topic); 

//Topic is NOT accessible
console.log('Topic outside is ' + topic); 
<!-- #7 Scope of Variables - Local vs Global -->
The scope of a variable limits from where you can access the variable. Variables within certain containers, such as objects and functions, are local those containers. Global variables are accessible from everywhere. 
Article about JS Scope: <a href="http://www.w3schools.com/js/js_scope.asp">http://www.w3schools.com/js/js_scope.asp</a>
Visit <a href="http://www.easyprogramming.net">EasyProgramming.net</a>