Some quick notes on handling checkboxes (and probably radio buttons, but I haven’t tested that) in JQuery.
To find a count of all checked items with the class Testbox.
$(".Testbox:checked").size();
To get a count of all of the unchecked items use this code:
$(".Testbox:not(:checked)").size();
To test an individual item with the ID Testbox1 use this:
$('#Testbox1').is(':checked');