window.onload = function(){
    var tables = document.getElementsByTagName("table");
    for ( var t = 0; t < tables.length; t++ ) {
        var rows = tables[t].getElementsByTagName("tr");
        for ( var i = 1; i < rows.length; i += 2 )
            if ( !/(^|\s)odd(\s|$)/.test( rows[i].className ) )
                rows[i].className += " odd";
    }
};