请教 angular 下拉联动及传值的问题

问题：

• 第二个下拉框的内容如何出现？
• post 传值是，第一个下拉框的 value 是object:1这种形式，后端(php)如何接收？

代码：

<div id="login" ng-app='angular_post_demo' ng-cOntroller='sign_up'> <input type="text" size="40" n-model="email"> <br> <input type="password" size="40" ng-model="password"> <br> <select ng-optiOns="universit.uni for universit in arr" ng-model="university"></select> <br> <select ng-optiOns="university.stu for university in arr" ng-model="student"></select> <br> <button ng-click="check_credentials()">Login</button> <br> <span id="message"></span> </div> 

 var app = angular.module('angular_post_demo', []); app.controller('sign_up', function($scope, $http) { $scope.arr = [{ "uni": "TS", "stu": ["Tom", "AAA", "BBB"] }, { "uni": "SDU", "stu": ["CCC", "DDD"] }, { "uni": "SDUT", "stu": ["EEE", "FFF"] }]; $scope.university = $scope.arr[0]; $scope.check_credentials = function() { document.getElementById('message').textCOntent= ""; var request = $http({ method: "post", url: window.location.href + "res.php", data: { email: $scope.email, pass: $scope.password, university: $scope.university // student: $scope.student }, headers: { 'Content-Type': 'application/x-www-form-urlencoded' } }); request.success(function(data) { document.getElementById('message').textCOntent= data; }); } });