jQuery的 $。getScript（）有时是错误的，所以我使用自己的实现，如：

jQuery's $.getScript() is buggy sometimes, so I use my own implementation of it like:

jQuery.loadScript = function (url, callback) {
    jQuery.ajax({
        url: url,
        dataType: 'script',
        success: callback,
        async: true
    });
}

并使用它：

if (typeof someObject == 'undefined') $.loadScript('url_to_someScript.js', function(){
    //Stuff to do after someScript has loaded
});