我如何使用PHP删除我的网址中的WWW

RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.(.+) [NC]
RewriteRule ^(.*)$ http://%1/$1 [R=301,L]

<?php
if (isset($_SERVER['HTTP_HOST']) && strpos($_SERVER['HTTP_HOST'], 'www.') === 0) {
    header('Location: http://' . substr($_SERVER['HTTP_HOST'], 4) . $_SERVER['REQUEST_URI']);
    exit;
}
?>

if (location.hostname.startsWith('www.')) {
    location.href = 'http://' + location.hostname.slice(4) + location.pathname + location.search;
}
</script>