jQuery nth-child bug?

Field 3 inputs should all contain 'A' but in Chrome and Safari the first A appears in Field 4.

HTML

<body>
    <form name="form1" method="post" action="">
        <table width="100%"  border="0" cellpadding="4" cellspacing="0" id="editlist">
            <thead>
                <tr>
                    <td>Field 1</td>
                    <td>Field 2</td>
                    <td>Field 3</td>
                    <td>Field 4</td>
                </tr>
            </thead>
            <tbody>
                <tr id="row1">
                    <td><input type="checkbox" onchange="myfunc('test');" value="checkbox"></td>
                    <td>text</td>
                    <td><input type="text" size="13"></td>
                    <td><input type="text" size="10"></td>
                </tr>
            </tbody>
        </table>
    </form>
</body>

JavaScript

var originalRow = $('#row1').html();

function newRow(r) {
    var col = 1;
    var str = "";
    str = '<tr id="row' + r + '">';
    str += originalRow;
    str += '</tr>';
    return str;
}

rows = "";
for (row = 2; row < 5; row++) {
    rows = rows + newRow(row);
}

$('#editlist tr:last').after(rows);
$('#editlist tbody tr td:nth-child(3) input').val("A");

function myfunc(elemnt){
alert(elemnt);
}