Here's the code for a tab box:
<!--First Tab-->
<div id="divfirsttab" style="display: block">
<a href="#" mce_href="#" onclick="return false;"><span>First Tab</span></a>
<a href="#" mce_href="#" onclick="document.getElementById('divfirsttab').style.display='none'; document.getElementById('divsecondtab').style.display='block'; return false;">
<span style="cursor: pointer">Second Tab</span></a>
<p>Your Content, 1st Tab</p>
</div>
<!--Second Tab-->
<div id="divsecondtab" style="display: none">
<a href="#" mce_href="#" onclick="document.getElementById('divsecondtab').style.display='none'; document.getElementById('divfirsttab').style.display='block'; return false;">
<span style="cursor: pointer">First Tab</span></a>
<a href="#" mce_href="#" onclick="return false;"><span>Second Tab</span></a>
<p>Your Text, 2nd Tab</p>
</div>