Navegar pelo DOM

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Como acessar via DOM o valor 'zzzzzzzzzzzzzzzzzzzzzz'

<div id="Regs">
	<table width="468" border="0" cellspacing="0" cellpadding="0">
 <tr>
 <td width="8" bgcolor="#FFFFFF"></td>
 <td width="460" align="left" valign="middle" bgcolor="#FFFFFF">
 <table width="459" border="0" cellspacing="0" cellpadding="0">
 <tr>
 <td height="5" colspan="3" class="text_medio"></td>
 </tr>
 <tr>
 <td width="324" colspan="2" align="left" valign="top" class="text_resultado_ib"></td>
 <td width="135" rowspan="3" align="right" valign="top" class="text_resultado_ib">zzzzzzzzzzzzzzzzzzzzzz</td>
 </tr>
 <tr>
 <td height="2" colspan="2" align="left" valign="top" class="text_resultado_topo"></td>
 </tr>
 <tr>
 <td width="30" align="left" valign="middle" class="text_endereco_ib"></td>
 <td width="294" align="left" valign="top" class="text_endereco_ib"></td>
 </tr>
 <tr>
 <td height="2" colspan="3" align="left" valign="middle"></td>
 </tr>
 <tr>
 <td height="10" rowspan="3" align="left" valign="middle"></td>
 <td height="5" colspan="2" align="left" valign="middle" class="ib_ser"></td>
 </tr>
 <tr>
 <td height="5" colspan="2" align="left" valign="middle"></td>
 </tr>
 </table>
 </td>
 </tr>
 <tr>
 <td height="1" colspan="2" align="center" valign="middle" bgcolor="D5D5D5"></td>
 </tr>
	</table>
</div>