I think freecodecamp is a great resource and I want to help promote and improve. On html lesson: Working with the iframe Element - How Do You Embed Videos onto Your Page Using the iframe Element? in:title they ask a question that is simply never mentioned. The question is Which attribute of the iframe element do you use instead of src if you want to embed direct HTML? The article never mentions anything about srcdoc. As we all know you can simply get the answer from Ai but that can lead to getting all answers from Ai especially freecodecamp is asking questions never mentioned.
Welcome to the forum @jhendrix619 ,
You may have overlooked the last sentence in that theory lecture, which says, " If you want to embed direct HTML within the iframe element you have to use the srcdoc attribute instead of src ."
Happy coding!