Other - Java script hide show text box based on dropdown selected.

hello i wish to show/appear and dissappear text box based on a the drop down item selected.

what do i have to add to the code below.? div?


under Comm_DEV
drop down selection.

if CELL_Phone then CELL_Phone text box shows/appears
if pager_device then CELL_Phone text box dissappears.

if email_Address only is selected then pager_device and CELL_Phone dissappears otherwise JOB_email_Address is shown ( even if CELL_Phone or pager_device is selected JOB_email_Address still appears)

Thank you
n
thanks in Adv
<!---------------------------------------------->
the field Comm_DEV gets populated with "E","CE","PE" when it is submit
when selected from the drop down.
<table>
<tr>
<td>Comm_DEV </td>
<td>
<SELECT name="Comm_DEV" size="1">
<OPTION Value = "EM">Please Select</OPTION>
<OPTION Value = "CE" <cfif Comm_DEV is "CE">selected</cfif>>CELL_Phone</OPTION>
<OPTION Value = "EM" <cfif Comm_DEV is "EM">selected</cfif>>email_Address Only</OPTION>
<OPTION Value = "PE" <cfif Comm_DEV is "PE">selected</cfif>>pager_device</OPTION>
</select> <!--------------------------></td>
</tr>
<!------Here are the text boxes to appear or dissapear CELL_Phone and JOB_email_Address-------------------->
<tr>
<td>CELL_Phone</td>
<td><cfoutput>
<cfif NOT len(trim(device_email_Address))><cfset device_email_Address = "@cingularme.com"></cfif>
<input type="Text" name="Device_email_Address" value="#Device_email_Address#" size="40" maxlength="40"> </td>




<td>
<b><font face="Verdana, Arial, Helvetica, sans-serif" size="2">JOBemail_Address</font></b><br>
<cfif not len(trim(JOB_email_Address))><cfset JOB_email_Address = "@balbal.org"></cfif>
<input type="text" name="JOB_email_Address" Value="#JOB_email_Address#" size="40"><br><br>
</cfoutput></td>
</tr>


</table>