Edit in JSFiddle

angular.module('MyApp', []).controller('MyCtrl', function ($scope) {
    $scope.secondsCounter = 0;
    setInterval(function () {
        $scope.secondsCounter = $scope.secondsCounter + 1;
        $scope.$apply();
    }, 1000);
});

<div ng-app="MyApp" ng-controller="MyCtrl">
    <span>{{secondsCounter}} seconds elapsed!</span>
</div>