jsLoader、cssLoader、imageLoader

	//js文件加载
	function jsLoader(url,callback){
		var script = document.createElement("script");
		script.src = url;
		script.type = 'text/javascript';
		script.language = 'javascript';
		script.onload = script.onreadstatechange = function(){
			isFunction(callback)&&callback();
		};
		document.getElementsByTagName("body")[0].appendChild(script);
	}
	
	
	//css文件加载
	function cssLoader(url,callback){
		var link = document.createElement("link");
		link.rel="stylesheet";
		link.type="text/css";
		link.href=url;
		link.onload = link.onreadstatechange = function(){
			isFunction(callback)&&callback();
		};
		document.getElementsByTagName("head")[0].appendChild(link);
	}
	
	//图片文件加载
	function imageLoader(url,targetId,callback){
		var img = document.createElement("img");
		img.src=url;
		img.onload = link.onreadstatechange = function(){
			isFunction(callback)&&callback();
		};
		document.getElementById(targetId).appendChild(link);
	}
	
	
	function isFunction(obj){
		return Object.prototype.toString.call(obj)==="[object Function]";
	}