Global Variables

GlobalAndLocalVariableIllustration.js

var global = "Global string";

function firstFunction(){
  var local = "Local string";
  alert(global);   //alerts out 'Global string'
  alert(local);    //alerts out 'Local string'
}

function secondFunction(){
  alert(global);   //alerts out "Global string"
  alert(local);    //errors, because `local` is only accessible in `firstFunction`
}

alert(local);    //errors, because `local` is only accessible in `firstFunction`