相关疑难解决方法(0)

我正在尝试编写一个超简单的解决方案来异步加载一堆JS文件.到目前为止,我有以下脚本.但是,当脚本未实际加载时,有时会调用回调,这会导致找不到变量错误.如果我刷新页面有时它只是工作,因为我猜文件是直接来自缓存,因此比调用回调更快,这是非常奇怪的？

var Loader = function () {

}
Loader.prototype = {
    require: function (scripts, callback) {
        this.loadCount      = 0;
        this.totalRequired  = scripts.length;
        this.callback       = callback;

        for (var i = 0; i < scripts.length; i++) {
            this.writeScript(scripts[i]);
        }
    },
    loaded: function (evt) {
        this.loadCount++;

        if (this.loadCount == this.totalRequired && typeof this.callback == 'function') this.callback.call();
    },
    writeScript: function (src) {
        var self = this;
        var s = document.createElement('script');
        s.type = "text/javascript";
        s.async = true;
        s.src = src;
        s.addEventListener('load', function (e) { self.loaded(e); …