How to display text when a SharePoint custom new form field which is a checkbox is selected (true)

For some reason I'm having a brain dead issue here,  I just can not remember how to show some text items when a sps 2013 custom form field is  selected it is a checkbox.

<tr>
 <td width="190px" valign="top" class="ms-formlabel">                              
<H3 class="ms-standardheader">
<nobr>CLE Eligible</nobr>
</H3>
</td>
<td width="400px" valign="top" class="ms-formbody">
<SharePoint:FormField runat="server" id="ff9{$Pos}" ControlMode="New" FieldName="CLE_x0020_Eligible" __designer:bind="{ddwrt:DataBind('i',concat('ff9',$Pos),'Value','ValueChanged','ID',ddwrt:EscapeDelims(string(@ID)),'@CLE_x0020_Eligible')}"/>
<SharePoint:FieldDescription runat="server" id="ff9description{$Pos}" FieldName="CLE_x0020_Eligible" ControlMode="New"/>
</td>
</tr>

I want to be able to if this field  is true then show  some text under the text box

message text for example:
These offices are eligible for CLE
Dallas
SF
Los Angeles
NY NY

Seems simple enough but I'm having a brain fart on the  code  XSL or javascript needed to complete this action...

thanks for the assistance...