var styleUrl = '/.style/standard/xhtml/';

	function include(filename)
	{
		var head = document.getElementsByTagName('head')[0];

		var scripts = head.getElementsByTagName('script');
		for(var i = 0; i < scripts.length; i++)
			if(scripts[i].src == filename) return false;

		var script = document.createElement('script');
		script.src = filename;
		script.type = 'text/javascript';

		head.appendChild(script);

		return true;
	}
	
	function extend(childClass, parentClass)
	{
		var f = function() {}
		
		f.prototype = parentClass.prototype;
		childClass.prototype = new f();
		childClass.prototype.constructor = childClass;
		childClass.parentClass = parentClass.prototype;
	}