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。。╮(╯▽╰)╭