Prompt confirm before Leaving edited html form

问题:

If user tries to leave unsaved edited form, a message box pop-up

"This page is asking you to confirm that you want to leave - data you have entered may not be saved. Leave Page and Stay on Page"

Can we invoke this confirmation box through some special function of browser? I want to implement it in AngularJS application

回答1:

Warlock's answer is partly right, but in doing so, you'd break testability.

In Angular, you'd want to use $window, and you'll want to watch $dirty on your form. You'll need to have a named form, notice name="myForm" below. Then you can $watch $dirty on the form in your $scope:

app.controller('MainCtrl', function($scope, $window) {
  $scope.name = 'World';
  var win = $window;
  $scope.$watch('myForm.$dirty', function(value) {
    if(value) {
      win.onbeforeunload = function(){
        return 'Your message here';
      };
    }
  });
});

HTML

<form name="myForm">
  Name: <input type="text" ng-model="name"/>
</form>

Here's a plunk to demonstrate: http://plnkr.co/edit/3NHpU1

回答2:

If you want to cancel the route change when you determine your form is dirty, you can do this:

$rootScope.$on('$locationChangeStart', function(event) {
  event.preventDefault();
});

This will cancel the routing and keep you on the current page.

回答3:

You could use the "onbeforeunload" event. The syntax is as follows:

window.onbeforeunload = function () {
    return "Your text string you want displayed in the box";
}

This event will popup that confirmation dialog that you described above asking whether or not the user truly wants to leave the page.

Hope this helps.

回答4:

I liked @blesh's answer, but I think it fails to account for internal url changes (for example, if you use ngView on your application and visit different internal views). window.onbeforeunload never gets called when the hash # changes. In this case, you have to listen to both window.onbeforeunload and $locationChangeStart:

app.controller('OtherCtrl', ['$scope', '$window', '$location', '$rootScope', function($scope, $window, $location, $rootScope) {
  $scope.message = "This time you get a confirmation.";
  $scope.navigate = function() {
    $location.path("/main");
  }
  var getMessage = function() {
    if($scope.myForm.$dirty) {
      return $scope.message;
    } else {
      return null;
    }
  }
  $window.onbeforeunload = getMessage;
  var $offFunction = $rootScope.$on('$locationChangeStart', function(e) {
    var message = getMessage();
    if(message && !confirm($scope.message)) {
      e.preventDefault();
    } else {
      $offFunction();
    }
  });
}]);

See plunkr here: http://plnkr.co/edit/R0Riek?p=preview

回答5:

You can easily protect your form with jQuery with this simple unobtrusive code. Put in just before your </body> closing tag.

(function () {
    jQuery('form').one('change', function () {
        window.onbeforeunload = function () {
            return 'Form protection';
        };
    });
})();

回答6:

I think you would need to use $window.alert or $window.confirm or beforeroutechange

Angular documentation