A reference to the browser's window object. While window
is globally available in JavaScript, it causes testability problems, because
it is a global variable. In angular we always refer to it through the
$window service, so it may be overridden, removed or mocked for testing.
Expressions, like the one defined for the ngClick directive in the example
below, are evaluated with respect to the current scope. Therefore, there is
no risk of inadvertently coding in a dependency on a global value in such an
expression.
<script>
angular.module('windowExample', [])
.controller('ExampleController', ['$scope', '$window', function($scope, $window) {
$scope.greeting = 'Hello, World!';
$scope.doGreeting = function(greeting) {
$window.alert(greeting);
};
}]);
</script>
<div ng-controller="ExampleController">
<input type="text" ng-model="greeting" aria-label="greeting" />
<button ng-click="doGreeting(greeting)">ALERT</button>
</div>