drag and drop for a form

I am trying to do a drag and drop cards into a shelf. I am doing this
for the drop:

<%= drop_receiving_element :slot2,{:onDrop => "function(element) {
$('slot2').replace('<td id=\"slot2\">' + element.id + '</

').addClassName('cardfill'); }"} %>

This does not seem to be working. When I press submit, the id is not
being sent. Does anyone know how to get something like this to work?