Remove content of hidden fields

Hi,

Do you mean that you want the value to be removed from the input on the fly in javascript because you have some custom javascript that reads this value and it needs to reflect the state of the parent field ?
Or do you mean that the value previously entered in the input is stored in the database and you don't want that to happen ?
While the first is a bit difficult, the second should already be the case without doing anything.

Supposing that you're talking about the first, the problem is that each field type can have different ways to store what the user provides. So the javascript needs to adapt to that. However, since the javascript of the custom field system doesn't know how the HTML of the type handles itself, it means that we would need to build a system where each custom field would add its own javascript to be triggered to empty itself. It's a lot of work for something which should be manageable easily in your own javascript if you're already have your own custom javascript code. Or maybe I'm missing something on what you're trying to do ?