JSFiddle - React, Tailwind, and code Playground

HTML

<table id = "outer_1">
    <tr>
        <td>
            <table id="inner_1">
                <tr>
                    <td>
                        <input type='textbox' ID="SelectME_1" runat="server" />
                    </td>
                    <td>
                        <input type='textbox' ID="SelectME_2" runat="server" />
                    </td>
                </tr>
            </table>
            <table id="inner_2">
                <tr>
                    <td>
                        <input type='textbox' ID="SelectME_3" runat="server" />
                    </td>
                    <td>
                        <input type='textbox' ID="SelectME_4" runat="server" />
                    </td>
                </tr>
            </table>
        </td>
    </tr>
</table>

JavaScript

var inputs = $('table#outer_1').find('input');
alert(inputs.length);