iframe element Defines an inline frame (ie a frame embedded in a document), br element Specifies a hard line break in the text, strong element Specifies that the enclosed text should be rendered in the browser as "strong" (usually bold) text. These elements allows child elements from interactive, embedded, heading, sectioning, phrasing, and metadata content categories.
Click the html element name in the punctuation list to advance the example in 'Tryit-Editor':