UIX/XML: checkBox controls

Question

I'm trying to use a databound checkBox on a form. In an event handler I'd like to retrieve the state of the checkBox, but it only has a value if it's checked. If the checkBox is unchecked I don't get the formaparameter of the checkBox at all.
I used something like this:
<form method="POST" name="mainForm">
<contents>
<checkBox selectedValue="ckbx@fti:data" value="Y" name="ckbx" id="ckbx">
Since we use a generic eventhandler for a number of different pages to write the formparameters back to an XML document, we cant haredcode the handling of checkBoxes.
Is there any way to get a formParameter for unchecked checkBoxes to an eventhandler ?
If not this would make checkBoxes unusable for us and probably for many other applications as well.
Thanks,
Guido

Answer 1

In HTML, an unchecked checkbox doesn't deliver any value. A lousy design choice,
I think, but that's the way it is! So, one approach is to just treat the
absence of the parameter as "not checked".
Another approach is to use some onClick behavior. I think the following would work:
  <checkBox name="foo" onClick="document.someForm.fooValue = document.someForm.foo.checked ? 'y' : 'n'"/>
  <formValue name="fooValue"/>Tedious (and error-prone) to write and rewrite this, so I'd consider wrapping that up
into a template.