///////////////////////////////////////

​

var onload_queue = [];

var dom_loaded = false;

​

function loadScriptAsync(src, callback) {

  var script = document.createElement('script'); 

  script.type = "text/javascript";

  script.async = true;

  script.src = src;

  script.onload = script.onreadystatechange = function() {

    if (dom_loaded) 

      callback();

    else 

      onload_queue.push(callback);

    script.onload = null;

    script.onreadystatechange = null;

  };

  var head = document.getElementsByTagName('head')[0];

  head.appendChild(script);

}

​

function domLoaded() {

   dom_loaded = true;

   var len = onload_queue.length;

   for (var i = 0; i < len; i++) {

     onload_queue[i]();

   }

   onload_queue = null;

};

​

///////////////////////////////////////

​

// Dean Edwards/Matthias Miller/John Resig

​

function init() {

  // quit if this function has already been called

  if (arguments.callee.done) return;

​

  // flag this function so we don't do the same thing twice

  arguments.callee.done = true;

​

  // kill the timer

  if (_timer) clearInterval(_timer);

​

  // do stuff

  domLoaded();

};

​

/* for Mozilla/Opera9 */

if (document.addEventListener) {

  document.addEventListener("DOMContentLoaded", init, false);

}

​

/* for Internet Explorer */

/*@cc_on @*/

/*@if (@_win32)

  document.write("<script id=__ie_onload defer src=javascript:void(0)><\/script>");

  var script = document.getElementById("__ie_onload");

  script.onreadystatechange = function() {

    if (this.readyState == "complete") {

      init(); // call the onload handler

    }

  };

/*@end @*/

​

/* for Safari */

if (/WebKit/i.test(navigator.userAgent)) { // sniff

  var _timer = setInterval(function() {

    if (/loaded|complete/.test(document.readyState)) {

      init(); // call the onload handler

    }

  }, 10);

}

​

/* for other browsers */

window.onload = init;

​

///////////////////////////////////////

​

// TEST USAGE

​

loadScriptAsync(

  "http://code.jquery.com/jquery-1.4.4.js", 

  function() {

      alert("script has been loaded");

   }

);

​

///////////////////////////////////////

​

​

​