MDN includes a “Permitted Content” section for elements, eg for button it says
> Phrasing content but there must be no Interactive content. If the <button> is the first child of a customizable select element, then it may also contain zero or one <selectedcontent> element.
“Ok, but what constitutes ‘phrasing content’ or ‘interactive content’?” you might ask. Those terms are links that give a very good overview of their constituent elements.
> Phrasing content but there must be no Interactive content. If the <button> is the first child of a customizable select element, then it may also contain zero or one <selectedcontent> element.
“Ok, but what constitutes ‘phrasing content’ or ‘interactive content’?” you might ask. Those terms are links that give a very good overview of their constituent elements.