[jQuery] sort table by class

[jQuery] sort table by class


hi,
i want create sort table in 3 tables byclass
the code:
        $(".box table").tableSorter({
            sortColumn: 'name',
            sortClassAsc: 'header-asc',
            sortClassDesc: 'header-desc',
            highlightClass: 'highlight',
            headerClass: 'header',
        });
but, return ERROR:
$(".caixa table").tableSorter is not a function