Conditionally include text or other directives. Usage:
<!--# if expr="..." --> ... <!--# elif expr="..." --> ... <!--# else --> ... <!--# endif -->
Only one level of nesting is possible.
<!--# if expr="$name" -->
A string comparison:
<!--# if expr="$name = text" --> <!--# if expr="$name != text" -->
Or a regex match:
<!--# if expr="$name = /text/" --> <!--# if expr="$name != /text/" -->
If there are variables in the text, they will have their values substituted.