nguage" id="html-language_xref4">HTML language</a>.
    An element
    <a href="terminology.html#must-requirement" id="must-requirement_xref22">must</a>
    not contain
    <a href="syntax.html#contents" id="contents_xref3">contents</a>
    or attributes that are not part of its content model.</p>
    <p>The
    <dfn id="contents" title="contents">contents</dfn>
    of an element are any
    <a href="syntax.html#syntax-elements">elements</a>,
    <a href="syntax.html#character-data" id="character-data_xref1