Help with simple (6 line) plugin

Help with simple (6 line) plugin

I found this plugin online at: http://geekswithblogs.net/ignu/archive/2008/10/19/125934.aspx and its supposed to work as a filter for tables.
you just do:
$("#myFilter").tableFilter("#myTable");

It works just fine with just one table... but if you do a second
$("#mysecondFilter").tableFilter("#mysecondTable");

then both filters will filter just the secondTable... I have no experience in writing plugins but Im sure there is an easy fix to this... anyone that has any ideas please help, heres the whole plugin code
/// <reference path="jquery.js"/>
$.fn.tableFilter = function(tableSelector) {
    table = $(tableSelector);
   
    updateTable = function() {
        table.find('tr:gt(0)').hide();
       
        table.find('td:contains("' + $(this).val() + '")').parents('tr').show();
    }
    $(this).keyup(updateTable);

}