In angular, ng-controller will form a scope. When using the form form, it will form a scope of the formController. When using ng-model, it will form a scope of the controllerScope. I want to ask Take a look, the instruction is require: 'ngModel', is the scope of the fourth parameter of link only the input scope? Search upward, or search the scope formed by the ng-model bound to the form in the parent scope?