javascript scoping - 1

gistfile1.js

// js scoping primer

// util
var _log = function(){
  var slice = [].slice,
      args = slice.call(arguments),
      len = args.length,
      i = 0;
  for(;i<len;i++) console.log(args[i])
};


/* #########################
 1 - SCOPE - GLOBAL
 in global scope, defining a variable or a function will create a property on this/window/self
*/

var a = 'foo';

_log( window.a )   //  'foo'
_log( this.a )     //  'foo'


_log( window === this )  //  true
_log( self === this )    //  true. Be careful with self.


// use var inside a function to avoid creating globals
function b(){

  var c = 'foo'; // local

  c2 = 'danneh'; // define without var keyword, will be global

  _log( window.c ) //  undefined

  _log( window.c2 ) //  'danneh'
} 

b();

// BUT, the function itself is still global
_log( b === window.b )