angular js勾选双向交互功能

1，下载框架包

<!doctype html>
<html ng-app="myApp">
<head>
<meta charset="UTF-8">
<meta name="Generator" content="EditPlus®">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<title>Document</title>
</head>
<body>
<div id="div1" ng-controller="Aaa">
<p>总价：{{oldPrice}()}</p>
<p>个数：<input type="text" ng-model="num"></p>
<p>邮费：{{target}}</p>
<p>单价：<input type="text" ng-model="price"></p>

</body>
</html>
<script src="js/angular.min.js"></script>

var m=angular.module("myAPP",[]);

m.controller("Aaa",["$socpe",fuction($scope)
{
$scope.price=2000;
$scope.num=5;
$scope.target=15;
$scope.oldPrice=(){
return $scope.price*$scope.num+$scope.target
}

//数据监听接口
$scope.$watch($scope.num,funtion(newVal,oldVal))
{
console.log(newVal);
console.log(oldVal);
return $scope.target=neVal>=9999?0:15;
}]);

</script>