PHP HTTPS to HTTP redirect

Hi, a while back you guys gave me a redirect to cause checkout pages to go to https. Now on one of our sites we're having issues after users go to the product pages (where they are redirected to https) and then leave to go back to the rest of the site. The rest of the site has google ads which use js files from an unsecure site so a pop up comes up in IE asking if they only want to few content that was delivered securely. There's no way to change the ads, I've looked for a solution. Is there a redirect that will take the page from https and go back to http? Here's the redirect I was given to go to https.

<?php if((!(isset($_SERVER['HTTPS']))) || ($_SERVER['HTTPS'] == "") || ($_SERVER['HTTPS'] == "off"))header("Location: https://" . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']); ?>

on the pages you do not wish to view using https, use this code:

<?php if((!(isset($_SERVER['HTTPS']))) || ($_SERVER['HTTPS'] == "") || ($_SERVER['HTTPS'] == "off"))header("Location: http://" . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']); ?>

I should have mentioned that I tried to change the "Location: https://" to "Location: http://" and didn't have any success. I just tried it again with what you gave me, but it still stays at https... Any other suggestions? I googled it but only found codes for http to https.

are you using an htaccess rule as well?

If you use an htacess rule, then that will override any php code.

no, i don't have any htaccess rules.

may be try using this instead:

if ($_SERVER['SERVER_PORT']==443) header("Location: http://" . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']);

Perfect, thanks Jason

you're welcome.

When redirecting from cart.php to index.php clicking the "Home" button a 404 error shows up.
I followed this post directions to redirect my https pages to http ones.
I added the following code to the cart page:
<?php if((!(isset($_SERVER['HTTPS']))) || ($_SERVER['HTTPS'] == "") || ($_SERVER['HTTPS'] == "off"))header("Location: https://" . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']); ?>
And the following to the index page:
<?php if ($_SERVER['SERVER_PORT']==443) header("Location: http://" . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']); ?>
Other links from https to http works fine but this. I checked the source code and the link seems Ok.

cart.php

send a copy of the index.php file, it is directing to a file called fakey.php for some reason.