document.write replacement using MooTools

document.write.moo.js

/*
---
source: http://gist.github.com/133677

provides: document.write
description: MooTools based document.write replacement
requires: MooTools

author: Thomas Aylott -- SubtleGradient.com
thanks: Daniel Steigerwald -- daniel.steigerwald.cz
license: MIT
...
*/
(function($){
	
	var wrapper  = new Element('div'),
		fragment = document.createDocumentFragment();
	
	document._writeOriginal = document.write;
	document.write = function(){
		var args = arguments, id = 'document_write' + $time().toString(36);
		if (!Browser.loaded)
			document._writeOriginal('<span id="' + id + '"></span>');
		else
			id = new Element('span',{id:id}).inject(document.write.context);
		
		function documentWrite(){
			var html = Array.join(args, '');
			document.addEvent('domready', function(){
				Array.filter(wrapper.set('html', html).childNodes, document.write.filter).each(function(node){
					fragment.appendChild(node);
				});
				(id = $(id)).parentNode.replaceChild(fragment, id);
			});
		}
		
		setTimeout(documentWrite, 0);
	};
	document.write.context = document.body;
	document.write.filter = function(el){ return true; };
	
})(document.id||window.$);

document.write.usage.moo.js

// USAGE EXAMPLES //


var start = +new Date;
var i = 1000; while (i--) {
	document.write(i+' ');
}
var end = +new Date;
alert(end-start);


window.addEvent('domready',function(){

	document.write('Lorem ipsum dolor sit amet');

	var myDiv = new Element('div');
	document.write.context = myDiv;
	document.write('Lorem ipsum dolor sit amet');
	myDiv.inject(document.body,'top');
	
});

document.write(1,2,3,4); // handles multiple arguments

document.write(); // doesn't break
document.write(null);

// Add a filter to stop certain things from being injected into your page
document.write.filter = function(el){
	return el && !$try(function(){ return el.get('tag') == 'link' })
};

document.write('<link rel="stylesheet" href="http://gist.github.com/stylesheets/gist/embed.css"/>');

Looks like they inject something into the DOM and then expect to be able to use it immediately (i.e. before DOMReady).
In that case, there needs to be some way for the document.write replacement to have a whitelist of things that simply cannot function without actually injecting into the DOM at that very instant.

using to document.write to add the span tag pretty much makes this useless as an approach unfortunately.