如何使用jquery动态加载js,css文件实现代码

$.extend({
includePath: ,
include: function(file) {
var files = typeof file == "string" ? [file]:file;
for (var i = 0; i < files.length; i++) {
var name = files[i].replace(/^\s|\s$/g, "");
var att = name.split(.);
var ext = att[att.length - 1].toLowerCase();
var isCSS = ext == "css";
var tag = isCSS ? "link" : "script";
var attr = isCSS ? " type=text/css rel=stylesheet " : " language=javascript type=text/javascript ";
var link = (isCSS ? "href" : "src") + "=" + $.includePath + name + "";
if ($(tag + "[" + link + "]").length == 0) document.write("<" + tag + attr + link + "></" + tag + ">");
}
}
});

//使用方法
$.includePath = http://hi.baidu.com/javascript/;
$.include([json2.js, jquery.tree.js, jquery.tree.css]);