ploneformgen show/hide fields based on selection field

We wanted to show/hide some fields in our multistage form created in Plone via ploneformgen. It is a neat trick with jQuery and here is how we did it:

• Open ZMI/yourSite
• Navigate to the form folder
• Add new Python script 
• Click Add and edit
• Paste the code

return \

"""

<script type="text/javascript">

$(document).ready(function() {

   $('#archetypes-fieldname-div-to-hide').hide();


$("#selection-field").change(function()

{

        if ($(this).val() == "I like this")

            $('#archetypes-fieldname-but_why').slideDown();

        else

        $('#archetypes-fieldname-but_why').slideUp();

    });

});

</script>

"""

Now open the form->edit->overrides and in the Header Injections Field enter the id of the python script as:
here/scriptID

works like a charm :)