var ag=navigator.userAgent.toLowerCase();

var full = ( (ag.indexOf('mozilla/5')!= -1) || (ag.indexOf('msie 5.5')!= -1) || (ag.indexOf('msie 6')!= -1) || (ag.indexOf('opera/7')!= -1) );

var ptnfull = '-f.html';
// Возможно перенаправлять "старые" броузеры
var ptnlite = '-l.html';

var pos = -1;
var loc = document.location.href;

/*
if ( full && (pos = loc.indexOf(ptnlite)) != -1 )
	document.location = loc.substring (0, pos) + ptnfull + loc.substring (pos+ptnlite.length);
else
if ( !full && (pos = loc.indexOf(ptnfull)) != -1 )
	document.location = loc.substring (0, pos) + ptnlite + loc.substring (pos+ptnfull.length);
*/