capturing deferred state with a closure

countdown.js

// a solution to http://blog.abhiomkar.in/2010/07/03/javascript-code-challenge-by-dropbox-team/
//

var countdown = function(num){
  for (var i = 0; i <= num; i += 1) {
    (function(i){ setTimeout(function(){ alert(num - i); }, i * 1000); })(i);
  }
}

countdown(5);