JavaScript design Pattern 1----Single-case mode

Definition: Ensure that a class has only one instance and provides a global interface for access:

is to accept: when we var a = new A (); var a1 = new A () is; A is equal to A1. How to achieve it, is the first time instantiation. The second is not the instance, but the first instantiation is returned:

Attach the general inertia Singleton idea:

Singleton.getinstance = (function () {    var instance = null;    return function (name) {        if (!instance) {            instance = new Singleton (name);        }        return instance;    }}) ()

Example of a login box on a book:

varCreateloginlayer =(function () {varDiv; returnfunction () {if(!Div) {Div= Document.createelement ('Div'); Div.innerhtml='I am a login'; Div.style.display='None';        Document.body.appendChild (DIV); }        returnDiv; }}) () document.getElementById ('Div1'). onclick =function () {varLoginlayer =Createloginlayer (); LoginLayer.style.display='Block'; }

General-purpose Inert single cases:

varGetsingle =function (FN) {varresult; returnfunction () {returnResult | | (Result = Fn.apply ( This, arguments)); }}varCreateloginlayer =function () {vardiv = document.createelement ('Div'); Div.innerhtml='Woshi Denglu'; Div.style.display='None';    Document.body.appendChild (DIV); returnDiv;}varCreatesingleloginlayer =Getsingle (Createloginlayer); document.getElementById ('Div1'). onclick =function () {varLoginlayer =Createsingleloginlayer (); LoginLayer.style.display='Block'; }    //when creating a unique iframe    varCreatesingleframe =Getsingle (function () {variframe = document.createelement ('iframe');        Document.body.appendChild (IFRAME); returniframe; }) document.getElementById ('Div1'). onclick =function () {varLoginlayer =Createsingleframe (); LOGINLAYER.SRC='http://baidu.com'    }

JavaScript design mode 1----Singleton mode