(function () {

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

	h.addStyle = function (styleStr) {
		var stl = document.createElement('style'),
			rules = document.createTextNode(styleStr);
		stl.setAttribute('type','text/css');
		this.appendChild(stl);
		if(stl.styleSheet && typeof stl.styleSheet.cssText == 'string') 
			stl.styleSheet.cssText = rules;
		else
			stl.appendChild(rules);
	}

	h.addStyleSheet = function (href) {
		var link = document.createElement('link');
		link.setAttribute('rel','stylesheet'),
		link.setAttribute('type','text/css'),
		link.setAttribute('href',href);
		this.appendChild(link);
	}

	h.condStyle = function (styleStr,cond) { if(cond) this.addStyle(styleStr); }

	h.condStyleSheet = function (href,cond) { if(cond) this.addStyleSheet(href); }

})()