It would be very nice if all unknown attributes to a #tag would go into the generated tag. "Unknown" here is all attributes where there is no meaning to the tag generator. For example:

#tag(Select "name='sel'" "onchange='do something in js'" ...)

would put the unknown attribute, onchange, in the generated tag:
<select name="sel" onchange="do somehting in js" ...)

Without this feature (and the #tag not implementing all standard html attributes) there will always be any case when the #tag cannot be used because of lack of attributes supported.

This should also make the #tag more easily implemented because many of the tags today is just forwarded to the resulting tag. Attributes with no assignment, like "disabled", should also be included.