Deprecated This feature has been removed from the Web. Though some browsers may still support it, it is in the process of being dropped. Do not use it in old or new projects. Pages or Web apps using it may break at any time.
This element should appear directly inside a rule element and is used to define conditions for the rule. Within the conditions can be placed content, member and triple elements. These may have attributes whose value is a variable name beginning with a question mark (?). When evaluating the rule for a particular RDF resource, the variables are replaced with values from the resource. If all variables can be replaced, the rule matched.
This element is used with Firefox 2/Mozilla 1.8 and earlier instead of the query element.
More information is available in the XUL tutorial.