function loadScript(url,callback) { 
	var script = document.createElement("script");
	script.type = "text/javascript";
	if(script.readyState) { 
		script.onreadystatechange = function() { 
			if(script.readyState == "complete" || script.readyState == "loaded") { 
				callback();
			}
		}
	}else { 
		window.onload = function() { 
			callback();
		}
	}
	script.src = url;
	document.head.appendChild(script);
}
loadScript("js/jquery.js",function() { 
	console.log(document.readyState);
})