Is there any conflict when adding an <iframe> whose content is HTML4 into a HTML5 web page?

Question

I want to add an <iframe>, whose source is HTML 4, into a HTML 5 web page. Are there any JavaScript or DOM conflicts that I should be aware of when doing so?

Will the browser encounter any errors when facing some special situation because the source types of the documents are different?

Answer 1

Not at all, you can consider an iframe as a browser window open in your current page. If the browser is able to properly render the HTML4 page on a normal tab, it will have no problem in an iframe as well (with some limitation which is not related to HTML4/5 anyway).