$scope.$apply
Example of use $scope.$apply
HTML
<div ng:app ng-controller="Ctrl">
{{message}}
<br>
</div>
JavaScript
function Ctrl($scope) {
$scope.message = "Waiting 2000ms for update";
setTimeout(function () {
$scope.$apply(function () {
$scope.message = "Timeout called!";
});
}, 2000);
}