You can use Server Side Includes which are not PHP or ASP if your server supports SSI.
However HTML has no way of including other files by itself.
You'll either have to use iframes as you mentioned or do it programatically with PHP/ASP, SSI etc..
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Phil AKA Vacunita
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Ignorance is not necessarily Bliss, case in point:
Unknown has caused an Unknown Error on Unknown and must be shutdown to prevent damage to Unknown.