The sidebar shows how you can use unordered subelements with a DTD, but unless there is a different compelling reason, it is better to use the attribute-style for unordered data.

副栏显示了如何可以使用带 DTD 的无序子元素。 但除非另有一个令人信服的原因，否则，对于无序数据，最好使用属性风格。

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That's a key attribute in a teen style landscape that has the masses behind the curve of those on the leading edge, resulting in delayed purchases as kids sort out who's wearing what.

FORBES: Magazine Article

Its wording states: "All the children of the eldest son of the Prince of Wales should enjoy the style, title and attribute of Royal Highness with the titular dignity of Prince or Princess prefixed to their Christian names".

BBC: Royal baby girl 'would be princess'