• 方法一

//方案一     var SingletonTester = (function () {         //单例方法         function Singleton(args) {             var args = args || {};             this.name = 'SingletonTester'; //方法对外的属性，另外一种方式就是返回对象             this.pointX = args.pointX || 6;             this.pointY = args.pointY || 10;         }         //单例实例         var instance;         //返回对象         return {             name: 'SingletonTester',             getInstance: function (args) {                 if (instance === undefined) {                     instance = new Singleton(args);                 }                 return instance;             }         };     })(); //直接执行该方法     //测试     var test = SingletonTester.getInstance({ pointX: 5 });     console.log(test.pointX);

• 方法二

function Universe() {       // 判断是否存在实例       if (typeof Universe.instance === 'object') {           return Universe.instance;       }       // 其它内容       this.start_time = 0;       this.bang = "Big";       // 缓存       Universe.instance = this;       // 隐式返回this   }   // 测试   var uni = new Universe();   var uni2 = new Universe();   console.log(uni === uni2); // true