Redirect only once to specific page

Hi everyone,
Once people arrive on my website, I would like them to be redirected to a specific page but only once. This means once they visited that page and go back to the main page, I don't want them to be redirected again.
So far I used this code : 
<script>
         setTimeout(function(){
            window.location.href = 'https://(mywebsite)';
         }, 30000);
</script>

But this means, once they visited the page and go back to the Main, they will be redirected again and again...

Any code to add to this?

Thanks

4 hours ago, DougM said:

Once people arrive on my website, I would like them to be redirected to a specific page

Instead of redirecting users, have you considered showing users a promotional pop-up?

3 hours ago, paul2009 said:

Instead of redirecting users, have you considered showing users a promotional pop-up?

Yes Paul I have tried but for what we need, I can't created a decent pop-up on Squarespace, so I created a Landing page. ( I need not only the email address of the visitor but also their name, phone number and more...)
I would like it to appear after 30 seconds tho.

To make the code run only once you could use a cookie or localStorage.

Instead of a one a done situation you may want to get fancier and have some kind of expiration or other way to reset your flag.

14 hours ago, creedon said:

To make the code run only once you could use a cookie or localStorage.

Instead of a one a done situation you may want to get fancier and have some kind of expiration or other way to reset your flag.

Yes, using cookie sounds great but unfortunately I am not good enough in coding. Newbie here.
Do you suggest any?
Thank you creedon