css selector id class

1Select an element with the ID "id" and the class "class":
2#id.class {
3}
4example:
5<div>
6  <strong id="id" class="class">
7      Foobar
8  </strong>
9  <strong class="class">
10      Foobar
11  </strong>
12</div>
13=> Will select the first <strong> element
14
15Select all elements with the class "class",
16which are decendents of a element with an ID of "id":
17#id .class {
18}
19example:
20<div id="id">
21	<strong class="class">Foobar</strong>
22</div>
23=> Will select the <strong> element

1css
2.class
3#id

1div#content.myClass.aSecondClass.aThirdClass /* Won't work in IE6, but valid */
2div.firstClass.secondClass /* ditto */
3