无法检测窗口是否已加载

我目前正在计算应用程序中打开的选项卡的数量。但是我的问题是我的脚本似乎无法检测到事件加载。这是我的代码。我正在使用HTML5网络存储和本机js。我不是使用jQuery来了解有关本机js的更多信息。

(function(w) {
    function Tabz(win, key) {
        this.name = '';
        this.storageKey = key;
        if(win.name != '')
            this.name = win.name;
        else {
            var windowArr = JSON.parse(localStorage.getItem(key)) || [];
            this.name = "tabz_"+ windowArr.length; 
            win.name = this.name;
            windowArr.push(this.name);
            localStorage.setItem(this.storageKey, JSON.stringify(windowArr) );
        }
    }

    Tabz.prototype.getStorage = function() {
            return localStorage.getItem(this.storageKey);
    }

    Tabz.prototype.removeWindow = function() {
            //remove window function here
    }

    var newWindow = new Tabz(w, 'counter');
    window.load =  function() {
        var count = JSON.parse(newWindow.getStorage()).length;
        alert(count!); // this wont execute so that I can check the count.
    }

   })(window);