代码如下:

var head = document.getElementsByTagName('head')[0];        var script = document.createElement('script');        script.type = 'text/javascript';        script.charset = 'GBK';        script.onload = script.onreadystatechange = function() {            if (!this.readyState || this.readyState === "loaded" || this.readyState === "complete" ) {                callback();                script.onload = script.onreadystatechange = null;            }        };        script.src= url;        head.appendChild(script);

这段代码实现了动态创建script标签,然后插入到head标签中.然后当js加载完毕的时候调用callback回调.

想解释点什么,但觉得实在没什么好说的...好吧...就这样吧...看看就行了...