If you only want to select an element that has, say, BOTH of the classes “first” and “selected”, but not all the elements that have EITHER classm you can just use “.first.selected” (no spaces between the class names) as your selector, and presto, it selects just elements with BOTH the “first” and “selected” classes. Not sure of the browser support, but it seems to work in all the browsers I tested.
