javascriptでブラウザ判別&ページ遷移

var userAgent = window.navigator.userAgent.toLowerCase();//ユーザーエージェント取得
var appVersion = window.navigator.appVersion.toLowerCase();//バージョンの取得

if (userAgent.indexOf("msie") > -1) {
if (appVersion.indexOf("msie 6.0") > -1) {
document.location = "aaa.php";
}
else if (appVersion.indexOf("msie 7.0") > -1) {
document.location = "bbb.php";
}
else if (appVersion.indexOf("msie 8.0") > -1) {
document.location = "ccc.php";
}
else if (appVersion.indexOf("msie 9.0") > -1) {
document.location = "ddd.php";
}
else if (appVersion.indexOf("msie 10.0") > -1) {
document.location = "eee.php";
}
else {
document.location = "fff.php";
}
}
else if (userAgent.indexOf("sleipnir") > -1) {
document.location = "ggg.php";
}
else if (userAgent.indexOf("firefox") > -1) {
document.location = "hhh.php";
}
else if (userAgent.indexOf("chrome") > -1) {
document.location = "iii.php";
}
else if (userAgent.indexOf("safari") > -1 & navigator.userAgent.indexOf('Mac') != -1) {
document.location = "jjj.php";
}
else if (userAgent.indexOf("safari") > -1) {
document.location = "kkk.php";
}
else {
document.location = "lll.php";
}