This is especially useful when integrating a Square payment option.

This is especially useful when integrating a Square payment option. The iFrame allows Square to work without the whole website having to be SSL certified (with HttpS pages)!

That is true, it will work, but it is not related to Square allowing it, it is just that https iFrames will generally work in HTTP page, but that is not a good practice. I found this article where you can read more: http://www.tinywebgallery.com/blog/iframe-do-not-mix-http-and-https

Thank you!

Thank you for your feedback. For the very light use of the payment integration, I'll stick with this and monitor how it works for my guests who RSVP and pay at this page. 
Claudia 
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Claudia Hommel --"Your Ticket to Paris"
1-773-509-9360
workinginconcert.org
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