html: element(s) / attribute(s) / reference(s)

• document(s) -- html, head, body
• external(s) -- style (<link href= rel= />), script (src=)
• header(s) -- h1, h2, ...,
• paragraph(s) -- p, quote
• link(s) -- a (href=)
• display(s) -- pre
• image(s) -- img (src, border, alt)
• media -- object
• block(s) -- div, iframe
• inline(s) -- span, em
• table(s) -- table, tr, td
• form(s) -- form, input