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']);