Why Square does not work in HTTP website?

My form causes a square can only be displayed on https dialog box to pop up. I am sure this has probably been answered before but the search on the forum is terrible.

Unfortunately, the Square integration will only work under secure webpages using HTTPS protocol, since your webpage is loaded under HTTP the integration refuses to work. 

If you would need to get the form and payment integration working, then you will need to either upgrade your website to HTTPS, you could contact your website administrator in order to ask about it, or you will need to use the direct link to your form, here is how to get it: 

Hope this helps.