<script src="https://cdn.staticfile.org/angular.js/1.6.6/angular.min.js"></script>

​

<div ng-app="myApp" ng-controller="myCtrl">

    <input type="text" ng-model="myInput" ng-blur="blur()">

    <p>输入的内容为：{{myInput}}</p>

    <p>变成小写：{{ x1 }}</p>

    <p>变成大写：{{ x2 }}</p>

  <p ng-switch = "x3">

      是不是字符串：

      <label ng-switch-when = "true">是</label>

      <label ng-switch-when = "false">不是</label>

      <label ng-switch-when = ""></label>

  </p>

     <p ng-switch = "x4">

      是不是数字：

      <label ng-switch-when = "true">是</label>

      <label ng-switch-when = "false">不是</label>

      <label ng-switch-when = ""></label>

  </p>

</div>

var app = angular.module('myApp', []);

app.controller('myCtrl', function($scope) {

    $scope.blur = function(){

        if($scope.myInput ==''){

          $scope.myInput = undefined;

        }      

          if(!isNaN($scope.myInput)){            

          $scope.myInput = Number($scope.myInput);

        }

        $scope.x1 = angular.lowercase($scope.myInput);

        $scope.x2 = angular.uppercase($scope.myInput);

        $scope.x3 = angular.isString($scope.myInput);          

    $scope.x4 = angular.isNumber($scope.myInput);       

    }

});