Here's a little trick to make an unchecked checkbox with a button for example:
Function:
function mf_setUnchecked(name, value, checked)
{
if (arguments.length<3) checked = false;
for (var i = 0; i < ff_elements.length; i++)
if (ff_elements[i][2]==name) {
var e = ff_getElementByIndex(i);
if (e.value == value) {
e.checked = checked;
break;
} // if
} // if
} // mf_setUnchecked
Custom code for the button:
function ff_MyButton_action(element, action)
{
switch (action) {
case 'click':
mf_setUnchecked('name','value');
break;
default:;
} // switch
} // ff_MyButton_action
it also works with the radio button.