I have to disagree. Allowing arbitrary HTML/JS code in any post in Steemit through iframes is not a good idea. It opens up too many paths for security vulnerabilities.
Selectively allowing some services (as is done for YouTube links) to be embedded is a better way to go. Services like Vimeo, Soundcloud, places where creative people post their stuff.
If you read their security statements, they block JS and cookie access and do not arbitrarily allow just any code.
Selectively allowing some services is what they do. Vimeo and Soundcloud are in the list.
The open source projects provide exactly what you asked for...
Try looking at the links.
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The issue I see is that it opens the gates too wide, and hands the keys over to someone else.
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There, you found one I can agree with.
Good thing it is open source so they can just take the good parts...
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Iframes work all over this thing called the internet. Again, they work.
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