<!DOCTYPE html>
<html lang="en" ng-app>
<head>
<meta charset="UTF-8">
<title>Document</title>
<script type="text/javascript" src="js/angular-1.3.0.js"></script>
<script>
function shop($scope){
$scope.items = {
"name":"apple",
"price":"5",
"quantity":"5",
"fre":"10"
};
$scope.sum = function (){
return $scope.items.price * $scope.items.quantity;
};
$scope.$watch($scope.sum,function(newVal,oldVal){
$scope.items.fre = newVal >= 100 ? 0 : 10;
});
}
</script>
</head>
<body ng-controller="shop">
<div >
<span>{{items.name}}</span><br/>
<span>{{items.price}}</span><br/>
<input type="text" ng-model="items.quantity"><br/>
<span>{{items.fre | currency:‘￥‘ }}</span><br/>
<span>{{sum() + items.fre | currency:‘￥‘}}</span>
</div>
</body>
</html>
原文：http://www.cnblogs.com/mayufo/p/4988023.html