如何在不使用$ _GET的情况下将javascript变量传递给PHP？

So im trying to set the php timezone through javascript, so users automatically have the time set properly to their timezome. Now i found this code online, but unfortunately it transfers the determined value of the javascript through a GET value. Is there a way i can use this, but not require the inclusion of the GET value in the URL? as this happens to break my website due to how the .htaccess ReWriterules are set.So im trying to set the php timezone through ja