(Should this be over in "Troubleshooting"?)

There might be simpler ways directly within cforms or PHP, but I did this kind of thing with jQuery. You'd need to check "Use custom input field NAMES & ID's" under cforms "Core Form Admin / Email Options", and then embed a script something along the lines of:

<script type="text/javascript">
jQuery(document).ready(function(){ 
	jQuery.noConflict();
	jQuery("#id_of_checkbox").change(function() { 

jQuery("#id_of_text_field).show(); 

});	
};
<script>
 

I've only been doing this a couple of weeks and I might be all wrong, but that's the way I went.

 

Regards,

Tim Meneely