Closures are functions that refer to independent (free) variables (name), that have been returned by an enclosing function (makeFunc), and can still refer to those variables when they are called (myFunc()). As such, the closure (makeFunc()) 'remembers' the environment in which it was created.

function makeFunc() {
  var name = "Mozilla";
  function displayName() {
    alert(name);
  }
  return displayName;
}

var myFunc = makeFunc();
myFunc();

See MDN

tags: closure, javascript, js