How to combine class and ID in CSS selector?

Question

If I have the following div:

<div class="sectionA" id="content">
    Lorem Ipsum...
</div>

Is there a way to define a style that expresses the idea "A div with id='content' AND class='myClass'"?

Or do you have simply go one way or the other as in

<div class="content-sectionA">
    Lorem Ipsum...
</div>

Or

<div id="content-sectionA">
    Lorem Ipsum...
</div>

Answer 1

In your stylesheet:

div#content.myClass

Edit: These might help, too:

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

and, per your example:

div#content.sectionA

Edit, 4 years later: Since this is super old and people keep finding it: don't use the tagNames in your selectors. #content.myClass is faster than div#content.myClass because the tagName adds a filtering step that you don't need. Use tagNames in selectors only where you must!