Can a div be used inside a figure in HTML5? Based on an older version of the spec.

html5spec.py

METADATA_ELEMENTS = ('command', 'link', 'meta', 'noscript', 'script', 'style')

PHRASING_ELEMENTS = ('a', 'abbr', 'area', 'audio', 'b', 'bdo', 'br', 'button',
    'canvas', 'cite', 'code', 'command', 'datalist', 'del', 'dfn', 'em', 'embed',
    'i', 'iframe', 'img', 'input', 'ins', 'kbd', 'keygen', 'label', 'map', 'mark',
    'meter', 'noscript', 'object', 'output', 'progress', 'q', 'ruby', 'samp',
    'script', 'select', 'small', 'span', 'strong', 'sub', 'sup', 'textarea',
    'time', 'var', 'video')

FLOW_ELEMENTS = ('address', 'article', 'aside', 'blockquote',
    'details', 'div', 'dl', 'fieldset', 'figure', 'footer', 'form',
    'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'header', 'hgroup', 'hr',
    'menu', 'nav', 'ol', 'p', 'pre', 'section', 'table', 'ul') + PHRASING_ELEMENTS

TRANSPARENT_ELEMENTS = ('a', 'audio', 'canvas', 'del', 'ins', 'map',
    'noscript', 'object', 'video')

ELEMENTS = {
    'a': None,
    'abbr': PHRASING_ELEMENTS,
    'address': FLOW_ELEMENTS,
    'area': None,
    'article': ('style',) + FLOW_ELEMENTS,
    'aside': ('style',) + FLOW_ELEMENTS,
    'audio': ('source',),
    'b': PHRASING_ELEMENTS,
    'base': None,
    'bdo': PHRASING_ELEMENTS,
    'blockquote': FLOW_ELEMENTS,
    'body': FLOW_ELEMENTS,
    'br': None,
    'button': FLOW_ELEMENTS,
    'canvas': None,
    'caption': FLOW_ELEMENTS,
    'cite': PHRASING_ELEMENTS,
    'code': PHRASING_ELEMENTS,
    'col': None,
    'colgroup': ('col',),
    'command': None,
    'datalist': ('option',) + PHRASING_ELEMENTS,
    'dd': FLOW_ELEMENTS,
    'del': None,
    'details': ('summary',) + FLOW_ELEMENTS,
    'dfn': PHRASING_ELEMENTS,
    'div': ('style',) + FLOW_ELEMENTS,
    'dl': ('dt','dd'),
    'dt': PHRASING_ELEMENTS,
    'em': PHRASING_ELEMENTS,
    'embed': None,
    'fieldset': ('legend',) + FLOW_ELEMENTS,
    'figcaption': PHRASING_ELEMENTS,
    'figure': ('figcaption',) + FLOW_ELEMENTS,
    'footer': FLOW_ELEMENTS,
    'form': FLOW_ELEMENTS,
    'h1': PHRASING_ELEMENTS,
    'h2': PHRASING_ELEMENTS,
    'h3': PHRASING_ELEMENTS,
    'h4': PHRASING_ELEMENTS,
    'h5': PHRASING_ELEMENTS,
    'h6': PHRASING_ELEMENTS,
    'head': ('title','base') + METADATA_ELEMENTS,
    'header': FLOW_ELEMENTS,
    'hgroup': ('h1','h2','h3','h4','h5','h6'),
    'hr': None,
    'html': ('head','body'),
    'i': PHRASING_ELEMENTS,
    'iframe': None,
    'img': None,
    'input': None,
    'ins': None,
    'kbd': PHRASING_ELEMENTS,
    'keygen': None,
    'label': PHRASING_ELEMENTS,
    'legend': PHRASING_ELEMENTS,
    'li': FLOW_ELEMENTS,
    'link': None,
    'map': None,
    'mark': PHRASING_ELEMENTS,
    'menu': ('li',) + FLOW_ELEMENTS,
    'meta': None,
    'meter': PHRASING_ELEMENTS,
    'nav': FLOW_ELEMENTS,
    'noscript': ('link','meta','style'),
    'object': ('param',),
    'ol': ('li',),
    'optgroup': ('option',),
    'option': None,
    'output': PHRASING_ELEMENTS,
    'p': PHRASING_ELEMENTS,
    'param': None,
    'pre': PHRASING_ELEMENTS,
    'progress': PHRASING_ELEMENTS,
    'q': PHRASING_ELEMENTS,
    'rp': PHRASING_ELEMENTS,
    'rt': PHRASING_ELEMENTS,
    'ruby': ('rt','rp') + PHRASING_ELEMENTS,
    'samp': PHRASING_ELEMENTS,
    'script': None,
    'section': ('style',) + FLOW_ELEMENTS,
    'select': ('optgroup','option'),
    'small': PHRASING_ELEMENTS,
    'source': None,
    'span': PHRASING_ELEMENTS,
    'strong': PHRASING_ELEMENTS,
    'style': None,
    'sub': PHRASING_ELEMENTS,
    'summary': PHRASING_ELEMENTS,
    'sup': PHRASING_ELEMENTS,
    'table': ('caption','colgroup','tbody','thead','tfoot','tr'),
    'tbody': ('tr',),
    'td': FLOW_ELEMENTS,
    'textarea': None,
    'tfoot': ('tr',),
    'th': FLOW_ELEMENTS,
    'thead': ('tr',),
    'time': PHRASING_ELEMENTS,
    'title': None,
    'tr': ('td','th'),
    'ul': ('li',),
    'var': PHRASING_ELEMENTS,
    'video': ('source',),
}

class HTML5Error(Exception):
    pass

def can_contain(outer, inner):
    if outer in TRANSPARENT_ELEMENTS:
        original_outer = outer
        outer = raw_input(">>> %s is transparent, what is the parent element? " % outer)
    elems = ELEMENTS.get(outer, [])
    if elems is not None:
        return inner in elems

if __name__ == '__main__':
    
    import sys
    
    def cmd_contains(*args):
        (outer, inner) = args
        is_valid = can_contain(outer, inner)
        if is_valid is None:
            print "%s cannot contain any elements" % outer
        else:
            contains = "can" if is_valid else "cannot"
            print "%s %s contain %s" % (outer, contains, inner)
    
    if len(sys.argv) < 3:
        raise ValueError("you must specify a command: html5spec.py <parent element> <child element>")
    
    cmd_contains(*sys.argv[1:])