angular过滤器可以使用一个管道字符（|）添加到表达式和指令中
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script src="https://cdn.staticfile.org/angular.js/1.4.6/angular.min.js"></script>
</head>
<body>
<div ng-app="myApp" ng-controller="myCtrl">
<input type="number" ng-model="quantity">
<input type="number" ng-model="price">
<p>总价：{{quantity*price|currency}}</p>
</div>
<script>
var app=angular.module('myApp',[]);
app.controller('myCtrl',function($scope){
$scope.quantity=100;
$scope.price=15;
})
</script>
</body>
</html>