Question

Im not sure why but for some reason when I click a td that has its checkbox already checked it does NOT deselect it.

$('table tr').click(function() {

    checkBox = $(this).children('td').children('input[type=checkbox]');

    if(checkBox.attr('checked'))
        checkBox.attr('checked', '');
    else
        checkBox.attr('checked', 'checked');
});

Answer 1

You want:

   if(checkBox.attr('checked'))
        checkBox.removeAttr('checked');
    else
        checkBox.attr('checked', 'checked');