jquery.delayedObserver.js

(function($) {
  $.fn.delayedObserver = function(delay, callback) {
    return this.keyup(function() {
      var element = this, $element = $(this);

      if(!$element.data('delayedObserver')) {
        $element.data('delayedObserver', setTimeout(function() {
          callback.apply(element);
          $element.removeData('delayedObserver');
        }, delay * 1000));
      }
    });
  };
})(jQuery);