Question: what about placing &a开发者_JAVA百科mp;nbsp; as the contents of the empty tag?
It validates, but is that considered a hack?
Regarding your question and with the detail from your comment, it is not a hack, but it is most likely not best practice either.
If you are looking to have a blank item for default, I would recommend --Select One--
instead, and if you are looking for a divider --------
would probably be your best option.
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