Angular:

http://angularjs.org/

HTML

<div ng-controller="MyCtrl">
  <input on-keyup="count = count + 1">
      {{count}}
</div>

JavaScript

var app = angular.module('myApp',[]);

app.directive('onKeyup', function() {
  return function(scope, elm, attrs) {
    elm.bind("keyup", function() {
      scope.$apply(attrs.onKeyup);
    });
  };
});

function MyCtrl($scope) {
}