How do I use jQuery .each() to find a child's children?

Question

Given many TABLE tags on a page, how do I select the TD childred on a selected table.

This is logical, but fails with this error:

Error: uncaught exception: Syntax error, unrecognized expression: [object Object]tr

My code

$(document).ready(function () {
    var selectedTable = $('table').eq('9');

    $(selectedTable).css('border','10px solid green');

    $(selectedTable + 'tr td').each(function(i) {
        $(this).css('border','10px solid blue');
    });

});

Answer 1

$(selectedTable).find('td').each(function (index, element) {
    ...
});

Answer 2

selectedTable is a jQuery object, not a string.
You can't use it in a selector.

Instead, you need to use jQuery's traversal API:

selectedTable.find('tr td')