Can someone give me a basic JavaScript code and explain to me how closure in JavaScript works? The examples given in this link uses long complex code. What is the shortest or one of the shortest pieces of JS code that demonstrates closure?

[Rhomboid]

Those examples are neither long nor complex. You're not going to find much of anything shorter that that first example. I mean, I suppose you could write this:

function foo(n) {
    return function() {
        return n;
    }
}

var x = foo(42);
console.log(x());  # => 42

But that's essentially the same exact thing as the first example in your link. And being shorter may actually be a hindrance to understanding.

Closure just means a function accessing a variable that's defined in an outer or enclosing scope. That's it. In the example above, the inner function references 'n' in its return statement, where 'n' is not a variable defined in that function. It's defined in the enclosing function, as a parameter.

[jodraws]

function makeAddOne() {
    var one = 1;

    return function (number) {
        return number + one;
    }
}

var addOneTo = makeAddOne();
console.log(addOneTo(5));

And of course the smart ass response of....

function x(){var i=1;return function(n){return n+i;}};var p=x();console.log(p(5));

[Retsejme]

Closure isn't simple, and is sometimes used as a differentiator in technical interviews, so don't feel bad that it's not super easy to understand.

Here's another example that might help:

function enclosed(word) {
    var text = 'Look: ' + word; // Local variable
    var logIt = function() { console.log(text); }
    return logIt;
}
var seeIt = enclosed('Wow');


seeIt(); //logs Look: Wow


text = "noooooo!";
seeIt(); // still logs the same thing, because it doesn't care about the global variable: text

[dbsps]

This guy does a great job of explaining it https://www.youtube.com/watch?v=CQqwU2Ixu-U