Scope Chain Example.

scopeChain.js

function b(){
  console.log(myVar);
}

function a(){
  var myVar = 2;
  console.log(myVar);
}

var myVar = 1;
a();

// what does b() log? ==> 1 

// the containing outer scope of function b is the global scope, because 
// what matters is where the function is defined, not where it is executed.
// It, lexically, is in the scope of the global environment.