One descendant of the action body should have a
uri attribute set to the member variable. This element and its descendants may use variables in place of attribute values. Variables are a question mark followed by a name. For a matched rule, each variable will be a reference to data within the datasource, determined from the query. If the same variable appears multiple times, it will have the same value in each place.
For more information, see Actions.
Inherited from XUL element