// Original code from Nathan Claire's blog
// http://nathanleclaire.com/blog/2013/11/16/the-javascript-question-i-bombed-in-an-interview-with-a-y-combinator-startup/
 
$(document).ready(function() {
  $('input').keypress(function() {
      if (this.timeoutId)
          window.clearTimeout(this.timeoutId);
      this.timeoutId = window.setTimeout(function () {
          $.ajax({
              // do some stuff
          });
      }, 200);
  });
});