利用jQuery的deferred对象实现异步按顺序加载JS文件_jquery

/*
Loading JavaScript Asynchronously
loadScript.load(["a.js", "b.js"]);
*/
var loadScript = (function() {
var loadOne = function (url) {
var dtd = $.Deferred();
var node = document.createElement('script');
node.type = "text/javascript";
var onload = function(){
dtd.resolve();
};
$(node).load(onload).bind('readystatechange', function(){
if (node.readyState == 'loaded'){
onload();
}
});
document.getElementsByTagName('head')[0].appendChild(node);
node.src = url;
return dtd.promise();
};
var load = function(urls) {
if(!$.isArray(urls)) {
return load([urls]);
}
var ret = [];
for (var i = 0; i ret[i] = loadOne(urls[i]);
};
return $.when.apply($, ret);
}
return {
load: load
};
})();

var a = "i am in a.js";
var b = "i am in a.js";

var a = "i am in b.js";
var b = "i am in b.js";