how to acces variables from another function?

How to acces variable from another function?
alert from function 1 takes the sum of the 2 variables from function 2

fun1();

function fun1() {
  alert("var two + var three = " + two + three);
}

function fun2() {
  var one = 1;
  var two = 2;
  var three = 3;
  var four = 4;
}

>Solution :

Either define these variables globally outside of both functions (a very bad practice for any real world program – but suitable enough for an example) – or provide them as arguments to the alert function.

var one, two, three, four;

fun1();

function fun1 ()
{
  fun2();
  alert("var two + var three = " + two +  three);
}

function fun2 ()
{
  one = 1;
  two = 2;
  three = 3;
  four = 4;
}

fun2();

function fun1 (one, two, three, four)
{
  alert("var two + var three = " + two +  three);
}

function fun2 ()
{
  fun1(1, 2, 3, 4);
}