javascript

异步js加载器

原文来自：snippets.barretlee.com，只是为了自己学习收集特意fork了一遍。如有侵权，联系删除：i@webcliwn.net。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
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); }, false);
        var head = document.getElementsByTagName('head')[0];
        head.appendChild(s);
    }
}

使用：

1
2
3
4
5
6
7
8
var l = new Loader();
l.require([
    "example-script-1.js",
    "example-script-2.js"],
    function() {
        // Callback
        console.log('All Scripts Loaded');
    });