角js选择框首先为空选项

Question

I am using angular 1.6.4 I want to display ages in select box so get values from controller, I use below code, but first field will come empty? please help me how to solve it

  <select ng-model="agefrom" name="agefrom" id="agefrom" class="select" style="width: 45%">
    <option ng-repeat="age in ages" ng-value="age">{{age}}</option>
  </select>

Answer 1

the first option comes empty because you did not select a ngModel. add value to ngModel and also use ng-options instead ng-repeat

 angular.module("app",[]) .controller("ctrl",function($scope){ $scope.ages = [2,3,4]; $scope.agefrom = $scope.ages[0] }) 

 <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script> <div ng-app="app" ng-controller="ctrl"> <select ng-model="agefrom" name="agefrom" id="agefrom" class="select" style="width: 45%" ng-options="age as age for age in ages"> </select> </div> 

Answer 2

You can simply use ng-init like this

<select ng-init="agefrom = ages[0]" 
    ng-model="agefrom" 
    name="agefrom" id="agefrom" class="select" 
    style="width: 45%">
    <option ng-repeat="age in ages" ng-value="age">{{age}}</option>
</select>