var navegador=navigator.appName;
	var ie=false;
	var ns=false;

	if (navegador=='Microsoft Internet Explorer'){var ie=true;}
	if (navegador=='Netscape'){var ns=true;}
	if(ie){document.write("<link rel='StyleSheet' href='css/estilos_html.css' type='text/css'>")};
    if(ns){document.write("<link rel='StyleSheet' href='css/ns_estilos_html.css' type='text/css'>")};