I have a table, and I want get the first “td” in all rows.

My jquery here:

$("table.SimpleTable tr td:first-child").css('background-color','red');

and my HTML here:

<table class='SimpleTable' border="1" ID="Table1">
        <tr>
            <td>Left</td>
            <td>Right</td>
        </tr>
        <tr>
            <td>Left</td>
            <td>Right</td>
        </tr>
        <tr>
            <td>Left</td>
            <td>Right</td>
        </tr>
        <tr>
            <td>Left</td>
            <td>
                <table border="1" ID="Table2">
                    <tr>
                        <td>AAA</td>
                        <td>AAA</td>
                        <td>AAA</td>
                    </tr>
                </table>
            </td>
        </tr>
        <tr>
            <td>Left</td>
            <td>
                <table border="1" ID="Table3">
                    <tr>
                        <td>BBB</td>
                        <td>BBB</td>
                        <td>BBB</td>
                    </tr>
                </table>
            </td>
        </tr>
    </table>

The problem here it get the first "td" in the nested table of the second "td".

Please help me!