Provided by module: Tags: RXML tags
Execute the contents if the previous <if> tag didn't,
or if there was a <false> tag above. This
tag also detects if the page's truth value has been set to false, which
occurrs whenever a runtime error is encountered. The <emit> tag, for one, signals this way when it did
not loop a single time.
The result is undefined if there has been no <if>,
<true>, <false> or other tag that
touches the page's truth value earlier in the page.
This tag is cache static (see the <cache> tag)
if the compatibility level is set to 2.5 or higher.