[SOLVED] Wrapping sidebar with class="nocontent"

I'd like to have something like i.e. surround a sidebar (footer, header, widget...) area with a class="nocontent". Preferably, I'd like to do it without having to modify the theme's code .

Why I want it? -- to tell Google Custom Search that the sidebar has a boilerplate content that's not relevant to the main content of the page. When Google Custom Search sees this tag, they ignore any keywords it contains and won't take them into account when calculating ranking for the Custom Search engine (see http://support.google.com/customsear...answer=2364585).