Hello Gilles,
First, I want to say thank you for taking the time to post this. Secondly I want to say how extremely helpful this is as it did resolve a similar problem I was having.
However, I did want to offer one amendment to this. Why? Because in some cases such as in for my client they wanted their payment or donate button to appear directly below other content that was on the page which they frequently edited. As such, I could not simply include that content in the 'offloaded' .html file which the iframe pointed to. So I had to figure out a way to still make use of the iframe, and yet keep it within the body of the existing Html module (because using the iframe module it would not allow me to place the iframe directly where they wanted).
So for someone who may also be looking for an answer to this question and wish to implement the same code but inline within their existing html module I offer this code as a reference
<iframe scrolling="no" name="Patient Payment" seamless="seamless" src="/portals/0/Forms/AuthNet.html">
However, by all means if you think this is not a good solution in comparison to the one you have suggested, please feel free to comment. However, this lets the iframe still offload to the alt. html page, but then the only thing in that page is what I need for the button, and the remainder of their site stays in tact to allow them to edit it as normal, and they can't mess up my image placement or button, because that code is hidden inside of the other file.
Again, I want to say I greatly valued this post, and it served its purpose well in spuring me in the right direction, then simply needing to apply my own knowledge of html to the situation to extrapolate a working solution.
Also, here is a good link to the 'official iframe rules' from w3c (Iframe W3C) which I used, and checked to ensure I stayed in the realm of HTML5 Compatibility.
Hopefully this may also help someone.
Thanks Again!
Make It a Great Day!
Dustin
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