mac = (navigator.appVersion.indexOf('Mac')!=-1)?true:false;
if(mac){
		document.write("<link rel='stylesheet' href='/css/extension_mac.css' type='text/css' media='all'>");
	}
else if(document.layers){
		document.write("<link rel='stylesheet' href='/css/extension_old.css' type='text/css'>");
	}