I have a form created using gravity forms wordpress plugin - see
[url removed, login to view]
If you look at the form and select the option Individual Documents £5 each... two new lists of document appear with checkboxes.
What I need is for the number of ticks to be counted and the 'Individual Document Sub-Total' field setting to £5 * number of boxes.
Gravity forms provides a hook which I have a working example of on the the site for you to add your code too. See [url removed, login to view] for an example of something similar.
The sub-total field needs to be read only.
The script must couple with new documents being added to the list increasing the number of checkboxes.