Angular: Empty Fiddle
http://angularjs.org/
by witq
HTML
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.20/angular.min.js"></script>
<div ng-controller="MyCtrl">
<pre ng-bind="model | json"></pre>
</div>
JavaScript
var myApp = angular.module('myApp',[]);
myApp.controller('MyCtrl', function($scope, $interval) {
$interval(function() {
$scope.a = Math.random() * 700 + 1;
$scope.b = Math.random() * 700 + 1;
}, 2000);
$scope.$watch('[a,b]', function(newValue, oldValue) {
$scope.model = {
new: newValue,
old: oldValue
}
}, true);
});