suggestion: strip_tags counterpart

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. What do you think about it? :-) Maciek