一個簡單的動態加載js和css的jquery代碼，用於在生成頁面時通過js函數加載一些共通的js和css文件。
//how to use the function below:
//$.include('file/ajaxa.js');$.include('file/ajaxa.css');
//or $.includePath = 'file/';$.include(['ajaxa.js','ajaxa.css']);(only if .js and .css files are in the same directory)
$.extend({
includePath: '',
include: function(file)
{
var files = typeof file == "string" ? [file] : file;
for (var i = 0; i < files.length; i++)
{
var name = files[i].replace(/^\s|\s$/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' " : " type='text/javascript' ";
var link = (isCSS ? "href" : "src") + "='" + $.includePath + name + "'";
if ($(tag + "[" + link + "]").length == 0) $("head").prepend("<" + tag + attr + link + "></" + tag + ">");
}
}
});
$.include('../js/jquery-ui-1.8.21.custom.min.js');
$.include('../css/black-tie/jquery-ui-1.8.21.custom.css');
將該函數寫入一個common.js文件中，在html中加載該common.js文件，就可以達到目的。
注意：
1.在html5中，<script>標簽已經不支持language屬性了，所以我刪除了：
var attr = isCSS ? " type='text/css' rel='stylesheet' " : " language='javascript' type='text/javascript' ";
中的language='javascript'
2.原作者在寫入js和css標簽時，用的是：
document.write("<" + tag + attr + link + "></" + tag + ">");
但是經過實踐，發現document.write（）方法會在寫入前清除原頁面的所有內容，也就相當於覆蓋的意思，這樣明顯達不到我的需要，我需要在加載頁面時動態的向頁面導入共通的js和css，而不能清除我原頁面的其他任何內容，所以查了下api，我改用了：
$("head").prepend("<" + tag + attr + link + "></" + tag + ">");
這個方法，$("head").prepend（）方法的作用是在<head>標簽的最前端追加寫入內容。
最後，再補充一個方法，也是通過共通js來實現，應該比上面這個方法更容易理解：
Dynamically loading external JavaScript and CSS files
To load a .js or .css file dynamically, in a nutshell, it means using DOM methods to first create a swanky new "SCRIPT" or "LINK" element, assign it the appropriate attributes, and finally, use element.appendChild() to add the element to the desired location within the document tree. It sounds a lot more fancy than it really is. Lets see how it all comes together:
function loadjscssfile(filename, filetype){
if (filetype=="js"){ //if filename is a external JavaScript file
var fileref=document.createElement('script')
fileref.setAttribute("type","text/javascript")
fileref.setAttribute("src", filename)
}
else if (filetype=="css"){ //if filename is an external CSS file
var fileref=document.createElement("link")
fileref.setAttribute("rel", "stylesheet")
fileref.setAttribute("type", "text/css")
fileref.setAttribute("href", filename)
}
if (typeof fileref!="undefined")
document.getElementsByTagName("head")[0].appendChild(fileref)
}
loadjscssfile("myscript.js", "js") //dynamically load and add this .js file
loadjscssfile("javascript.php", "js") //dynamically load "javascript.php" as a JavaScript file
loadjscssfile("mystyle.css", "css") ////dynamically load and add this .css file