html代码

 <div ng-controller="calcCtrl"><select ng-model="type"><option value="active">动态响应模式</option><option value="static">手动点击模式</option></select><input type="text" ng-model="num1"><select ng-model="operator"><option value="1">+</option><option value="2">-</option><option value="3">*</option><option value="4">/</option></select><input type="text" ng-model="num2"><button id="bResult" type="button" ng-click="calculate()">=</button><span>{{result}}</span></div>

<select>标签<option>里面传的参数是value里的值

js代码

'use strict';var app = angular.module('app', []);app.controller('calcCtrl', function($scope, myService) {$scope.type = 'active';$scope.operator = '1';$scope.num1 = 0;$scope.num2 = 0;$scope.result = 0;$scope.calculate = function() {$scope.result =myService.getResult(Number($scope.num1), Number($scope.num2), $scope.operator);};var activeModeListen;$scope.$watch('type', function(newType) {if(newType == 'active') { //自动计算$('#bResult').attr('disabled', 'true');activeModeListen = $scope.$watchGroup(['num1', 'num2', 'operator'], function() {$scope.result = myService.getResult(Number($scope.num1), Number($scope.num2), $scope.operator);});}else if(newType == 'static') { //需要按等号activeModeListen();$('#bResult').removeAttr('disabled');}});}).factory('myFactory', function() {var func = {};func.add = function(a, b) {if(a.toString().indexOf('.') != -1&& b.toString().indexOf('.') != -1) {var sq1,sq2,m;try {sq1 = a.toString().split(".")[1].length;}catch (e) {sq1 = 0;}try {sq2 = b.toString().split(".")[1].length;}catch (e) {sq2 = 0;}m = Math.pow(10,Math.max(sq1, sq2));return (a * m + b * m) / m;}else {return a + b;}};func.minus = function(a, b) {return a - b;};func.multiply = function(a, b) {return a * b;};func.divided = function(a, b) {return a / b;};return func;//将声明的func对象返回}).service('myService', function(myFactory) {this.getResult = function(m, n, operator) {var regExp = /[0-9]+/;if(!regExp.test(m) || !regExp.test(n)) {alert('must input number instead of others type of variable')}else {if(operator == '1') {return myFactory.add(m, n);}else if(operator == '2') {return myFactory.minus(m, n);}else if(operator == '3') {return myFactory.multiply(m, n);}else if(operator == '4') {return myFactory.divided(m, n);}}};});

js小数运算出现多位小数的解决方案

function addNum (num1, num2) {var sq1,sq2,m;try {sq1 = num1.toString().split(".")[1].length;}catch (e) {sq1 = 0;}try {sq2 = num2.toString().split(".")[1].length;}catch (e) {sq2 = 0;}m = Math.pow(10,Math.max(sq1, sq2));return (num1 * m + num2 * m) / m;
}
alert(addNum(0.1, 0.2));

工厂提供公用的方法
服务里面写逻辑关系实现某一个模块的功能，比如：一个登录注册界面，可以写两个服务