+> filters, you should first be familiar with HTML syntax,
+ and, of course, regular expressions. By default, filters are only applied
+ to the document content, but can be extended to the headers with
+ the supplemental actions:
+ <A
+HREF="actions-file.html#FILTER-CLIENT-HEADERS"
+>filter-client-headers</A
+> and
+ <A
+HREF="actions-file.html#FILTER-SERVER-HEADERS"
+>filter-server-headers</A
+>.</P