Switch content of DIV with another set DIVs with a timer

I have 3 divs in a html page, 2 divs should be hiddent always but theire content should be displayed in another div and this content should be changed every x seconds. Hows that possible using jquery/javascript?

<div id="contentA">
    <!-- Some contents goes here, and it should be hidden -->
    </div>

    <div id="contentB">
    <!-- Some contents goes here, and it should be hidden -->
    </div>        

    <div id="displayArea">
    <!-- switch between contentA and contentB on a timer say every 5 seconds -->
    </div>