var strategies = { "S": function(salary) {  return salary * 4; }, "A": function(salary) {  return salary * 3; }, "B": function(salary) {  return salary * 2; }};// 接收請求var calculateBonus = function(level, salary) { return strategies[level](salary);};// 測試console.log(calculateBonus("S", 20000));console.log(calculateBonus("A", 20000));console.log(calculateBonus("B", 20000));

/* 校驗策略對象 */var validateStrategies = { isEmpty: function (val, errorMsg) {  if (!val) {   return errorMsg;  } }, isURL: function (val, errorMsg) {  if (!new RegExp("^(http://////|https://////)?([//w//-]+//.)+[//w//-]+(///[//w//-//.///?//@//%//!//&=//+//~//://#//;//,]*)?$").test(val)) {   return errorMsg;  } }, isEmail: function (val, errorMsg) {  if (!new RegExp('//w+((-//w+)|(//.//w+))*//@[A-Za-z0-9]+((//.|-)[A-Za-z0-9]+)*//.[A-Za-z0-9]+').test(val)) {   return errorMsg;  } }, isMaxLength: function (val, length, errorMsg) {  if (val.length > length) {   return errorMsg;  } }, isMinLength: function (val, length, errorMsg) {  if (val.length < length) {   return errorMsg;  } }};/* validator類 */var validator = function () { // 緩存驗證策略 this.cache = [];};/** * 添加要驗證的策略 * @param dom  要驗證的dom元素 * @param rules  驗證規則 */validator.prototype.add = function (dom, rules) { var self = this; for (var i = 0, rule; rule = rules[i++];) {  (function (rule) {   var strategyAry = rule.strategy.split(":");  // ["isMaxLength", "10"]   var errorMsg = rule.errorMsg;     // "內容長度不能超過10"   self.cache.push(function () {    var strategy = strategyAry.shift();   // "isMaxLength"    strategyAry.unshift(dom.value);    // ["1@qq", "10"]    strategyAry.push(errorMsg);     // ["1@qq", "10", "內容長度不能超過10"]    return validateStrategies[strategy].apply(dom, strategyAry);   });  })(rule); }};/* 開始校驗 */validator.prototype.start = function () { for (var i = 0, validateFunc; validateFunc = this.cache[i++];) {  var errorMsg = validateFunc();  if (errorMsg) {   return errorMsg;  } }};// 測試<label for="email">郵箱：</label><input type="text" name="email" value="1@qq">var validatorInstance = new validator();validatorInstance.add( document.getElementsByName("email")[0],  [{  strategy: "isEmpty",  errorMsg: "內容不能為空" },{  strategy: "isMaxLength:10",  errorMsg: "內容長度不能超過10" },{  strategy: "isEmail",  errorMsg: "email格式不對" }]);errorMsg = validatorInstance.start();