<?php

if (preg_match("/Opera (\d)/i",$HTTP_USER_AGENT,$v)) {
    if (($version=$v[1])>4) $type=1;
    else $type=2;
}
elseif (preg_match("/MSIE (\d)/i",$HTTP_USER_AGENT,$v)) {
    if (($version=$v[1])>4) $type=1;
    else $type=2;
}
elseif (preg_match("/Mozilla(?:\/|\s)(\d)/i",$HTTP_USER_AGENT,$v)) {
    if (($version=$v[1])>4) $type=1;
    else $type=2;
}
else {
    $version="unknown";
    $type=2;
}

switch ($type) {
    case 1: $StyleSheet=compliant.css; break;
    case 2: $StyleSheet=older.css; break;
    default: StyleSheet=older.css; break;
}
?>