angularjs 提示消息未正常发送

Question

当没有下拉菜单 selected 时出现消息，但是当 selected 任何一个或多个下拉菜单时，消息也会出现请 select 至少 one.Below 是我的 angularjs

$scope.check = function () {


 if ($scope.landing.class == null || $scope.landing.class == undefined|| $scope.landing.class == "" && $scope.landing.fueltype == undefined || $scope.landing.fueltype == null || $scope.landing.fueltype == "" && $scope.landing.transmiss == null || $scope.landing.transmiss == undefined || $scope.transmiss == "" && $scope.landing.driving == null || $scope.landing.driving == undefined || $scope.driving == "" && $scope.landing.pick == null || $scope.landing.pick == undefined || $scope.landing.pick == "" && $scope.landing.stat == null || $scope.landing.stat == undefined || $scope.landing.stat == "") {
            alert('Please select atleast one')
        }
    }

Answer 1

您可能需要额外的括号...

if (($scope.landing.class == null || $scope.landing.class == undefined || $scope.landing.class == "" )
&& (
$scope.landing.fueltype == undefined || $scope.landing.fueltype == null || $scope.landing.fueltype == "" )
&& (....

但总的来说这很难看，您必须找到一种 better/smarter 方法来进行此验证..