获取一个表格的一行的值

 var str = "";
        $("table tr").each(function (index, value) {
            var text = $(this).children("td").eq(2).text();
            if (index == 0) {
                str = text;
            } else {
                str += "," + text;
            }
        })
        alert(str);





<table>
    <tr>
        <td>a1</td>
        <td>aa</td>
        <td>1</td>
    </tr>
    <tr>
        <td>a2</td>
        <td>aa</td>
        <td>2</td>
    </tr>
    <tr>
        <td>a3</td>
        <td>aa</td>
        <td>3</td>
    </tr>
</table>