任性，新建对象不用new

先看最简单的一个例子：

 window.meng = window.meng || {};
 (function () {

     /**
      *
      * @param {Number}width
      * @param {Number}height
      * @param {String}color
      * @constructor
      */
     function CreateDiv(width, height, color) {
         this.oWidth = width;
         this.oHeight = height;
         this.oColor = color;
     }

     CreateDiv.prototype.render = function () {
         var div = document.createElement("div");
         div.style.width = this.oWidth + "px";
         div.style.height = this.oHeight + "px";
         div.style.backgroundColor = this.oColor;
         return div;
     };
     meng.CreateDiv = CreateDiv;
 })();

 (function () {

     var div=new meng.CreateDiv(100,100,"red");
     document.body.appendChild(div.render());
 })();

上面是一个简单在页面添加div的例子。

当去掉new,的时候在运行会出现

但是我经常忘记，写new，又懒得去改，所以马虎人有马虎人的方法。

“轮子代码”这样改写

 window.meng = window.meng || {};
 (function () {

     /**
      *
      * @param {Number}width
      * @param {Number}height
      * @param {String}color
      * @constructor
      */
     function CreateDiv(width, height, color) {
         this.oWidth = width;
         this.oHeight = height;
         this.oColor = color;
         if (!(this instanceof CreateDiv)) {
             return new CreateDiv(width, height, color);
         }
     }

     CreateDiv.prototype.render = function () {
         var div = document.createElement("div");
         div.style.width = this.oWidth + "px";
         div.style.height = this.oHeight + "px";
         div.style.backgroundColor = this.oColor;
         return div;
     };
     meng.CreateDiv = CreateDiv;
 })();

就会发现不报错了。。╮(╯▽╰)╭