As already mentioned, you need to use $apply:
$apply() is used to execute an expression in angular from outside of the angular framework. (For example from browser DOM events, setTimeout, XHR or third party libraries). Because we are calling into the angular framework we need to perform proper scope life cycle of exception handling, executing watches.
For example:
var element = angular.element(document.querySelector('body'));
var service = element.injector().get('myService');
var scope = element.scope();
scope.$apply(function () {
service.somevar = true;
});