posted 11 years ago
"rendered" means that a graphic element is drawn on the resulting webpage. If you set "rendered=false" on an element, that element (and its childred) will not be displayed.
"updated" isn't actually a formal JSF term, but all it means usually is that the web page is re-drawn. AJAX uses a concept known as "partial page updating" to redraw only a section of the page without erasing and redrawing the whole page.
When a page (or page parts) is updated, the rendered= values for the elements being updated will be applied according to their current values. So you can use a partial page update to show and hide a section of a page.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.