How to apply two CSS classes to a single element

Question

Can i apply 2 classes to a single div or span or any html element? For example:

aa

I tried and

Answer 1

As others have pointed out, you simply delimit them with a space.

However, knowing how the selectors work is also useful.

Consider this piece of HTML...

Using .a { ... } as a selector will select the first and third. However, if you want to select one which has both a and b, you can use the selector .a.b { ... }. Note that this won't work in IE6, it will simply select .b (the last one).