cycling jQuery_Succinctly | Page 45
// By index.
alert($('li:nth-child(1)').text()); // Alerts "1".
// By even.
alert($('li:nth-child(even)').text()); // Alerts "246810".
// By odd.
alert($('li:nth-child(odd)').text()); // Alerts "13579".
// By equation.
alert($('li:nth-child(3n)').text()); // Alerts "369".
// Remember this filter uses a 1 index.
alert($('li:nth-child(0)').text()); // Alerts nothing. There is no 0 index.
})(jQuery);