Use this to dynamically register
outputfilters to operate on
a template's output before it is
displayed. See
template output
filters
for more information on how to set up an output filter function.
The php-function callback function can be either
a string containing the function name
an array of the form
array(&$object, $method) with
&$object being a reference to an
object and $method being a string
containing the method-name
an array of the form
array(&$class, $method) with
$class being a classname and
$method being a class method of that
class.