I have a client called YumFinder that has a secure shopping cart page that needed to call a non-secure form to continue shopping. My first approach was to include a link to the non-secure page (http):
With a browser like Internet Explorer 8.0 this works OK however with FireFox (Safari, Opera, Chrome) there is a warning dialog that pops up telling you that the form you are calling is not secure (http) while you are on a secure page (https).
I came up with a fix to avoid these security warnings. On the secure page I use a link to a PHP script which is also considered a secure page (https):
Then in the PHP script I redirect to my non-secure page:
The non-secure page (http) can now do it's work: