Question

Suppose I have a JavaScript function. and it contain a variable x;

function A(){
   var x = 12+34;
}

Is it possible to access x from outside function x?

Answer 1

No, the ability to do so would not make any sense. Suppose we changed your function slightly and called it 3 times:

function x(n){
   var x = n+34;
}

x(1), x(2), x(3);

At this point, the function has run 3 times, so the variable x has been created 3 times — which x would you expect to be able to access? Then there’s garbage collection; how could references and data be cleared from memory if the browser had to keep variables alive once they’re no longer in scope?

If you want to, you can do something like this:

function x() {
    x.x = 12+34;
}
x();

or, if the variable will be static/constant as you have it

function x() { }
x.x = 12+34;

or finally, as others have pointed out, by declaring x under a different name outside of the function’s scope:

var y;
function x() {
    y = 12+34;
}
x();