var agt=navigator.userAgent.toLowerCase();

var styles_type = 'ie';

if (agt.indexOf("msie") != -1){
	styles_type = 'ie';
}
else if (agt.indexOf("gecko/") != -1){
	styles_type = 'gecko';
}

document.write("<link rel='stylesheet' type='text/css' href='../css/styles.css'>");
document.write("<link rel='stylesheet' type='text/css' href='../css/styles_" + styles_type + ".css'>");