$(document).ready(function(){
            $('table.striped tbody').each(function(){$(this).find('tr:odd').addClass('alt');});
            $('table.dualstriped tbody').each(function(){$(this).find('tr:odd').addClass('alt').end().find('tr:nth-child(4n+4)').addClass('alt2');});
            $('table.average tbody').each(function(){$(this).find('tr:not([class*="header"]):even').addClass('alt');});
            $('table.average tbody').each(function(){$(this).find('tr:not([class*="header"]):odd').addClass('alt2');});
            // Note: ":odd" starts at zero for the index, whereas ":nth-child(odd)" starts at 1
});