function checkSelection(trigger_item) {
    $('#books_all').attr('checked', true);
    $('.testament').each(function() {
        testament = $(this).attr('id').match(/^testament_(\d+)$/)[1];
        allSelected = $('.testament_' + testament + ':checked').size() == $('.testament_' + testament).size();
        $(this).attr('checked', allSelected);
        if(!allSelected) {
            $('#books_all').attr('checked', false);
        }
    });
}


$(function() {
    /*TODO
    $('input[type=checkbox]').checkbox({
        empty: '/typo3conf/ext/jongerenbijbel/res/images/empty.png'
    });
    */
    $('.testament').click(function() {
        testament = $(this).attr('id').match(/^testament_(\d+)$/)[1];
        $('.testament_' + testament).attr('checked', $(this).attr('checked'));
    });

    $('#books_all').click(function() {
        $('.testament, .book').attr('checked', $(this).attr('checked'));
    });
    $('#books_all, .testament, .book').click(function() {
        checkSelection($(this));
    });    
    checkSelection();
});