find 3rd element of a list using dom code example

Example 1: select 2nd td jquery

$(".location table tbody tr td:first-child").addClass("black");
$(".location table tbody tr td:nth-child(2)").addClass("black");

Example 2: jquery select the 3rd row of a table

$('.itemTable').eq(2);
//this will grab the 3rd row of the table with the class itemTable