javascript: Load javascript resources asynchronously. Accepts additional parameters that can be passed to the specified callback function

async_load.js

/**
 * Load javascript resources asynchronously. Accepts additional parameters that can be passed to the specified callback function 
 * Author: Frederick King 
 * Date:  3/8/2012
 * References/Credits : http://css-tricks.com/thinking-async/ , http://mathiasbynens.be/notes/async-analytics-snippet
 *
 **/
 
var async_load_js = function( url, callback ){
	var js, args, rs, s;	
	/* Build script element */
	js = document.createElement('script');
	/* In IE6 there is a use case where this could fail. If you care about IE6 support you'll probably want to use location.protocol */
	js.src = '//' + url;
	js.type = 'text/javascript';
	js.async = 'true';
	/* If there are more than 2 args pass the additional args to the callback function as parameters */
	args = arguments.length > 2 ? Array.prototype.slice.call( arguments, 2 ) : [];	
	/* Handle callback function */
	js.onload = js.onreadystatechange = function(){
		rs = this.readyState;
		if (rs && rs != 'complete' && rs != 'loaded') return;
		try { callback.apply(this, args) } catch (e) { console.log(e); }
	};
	/* Finally append the script */
	s = document.getElementsByTagName('script')[0];
    s.parentNode.insertBefore(js, s);
};

/* Example Usage */
async_load_js('ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js', function(){
	console.log("script loaded", arguments);
}, 'cbparam1','cbparam2');