Replacing HTML

Replacing HTML

I am quite new to JQuery. After some struggling through some guides and tutorials I am still not where I want to be. Maybe you guys can help me out.

I am looking for an way to add an class to an specific string of html. Or hide the whole string.

The string is: (where VARIABLE is some variable text)
<li class="VARIABLE"><span>Cheese</span></li>



How can I add an extra class to the li? Or delete/hide the whole string?

Thanks in advance