Because I'd like to strip much less tags than I'd like to remain in the HTML file (and I suppose there are more people who would like such a feature) I'd suggest to accompany strip_tags with its counterpart:

string strip_tags (string str [, string allowable_tags])

in the following way (more or less):

string strip_some_tags (string str [, string not_allowable_tags])

or enhance strip_tags in order to allow only these tags which are not
allowed to exist in the resulting string.