JSFiddle - React, Tailwind, and code Playground

HTML

<table id="inputsTable">
    <tr>
        <td><input class="td_in" type="number" /></td>
        <td><input class="td_in" type="number" /></td>
        <td><input class="td_out" type="number" /></td>
        <td><input class="td_in" type="number" /></td>
    </tr>
     <tr>
        <td><input class="td_in" type="number" /></td>
        <td><input class="td_in" type="number" /></td>
        <td><input class="td_in" type="number" /></td>
        <td><input class="td_out" type="number" /></td>
    </tr>
     <tr>
        <td><input class="td_in" type="number" /></td>
        <td><input class="td_out" type="number" /></td>
        <td><input class="td_in" type="number" /></td>
        <td><input class="td_out" type="number" /></td>
    </tr>
</table>

JavaScript

$(document).keypress(function(e){
    if( e.which == 13 && e.target.nodeName == 'INPUT'){
        var inputs = $("#inputsTable input.td_in");
        alert(inputs.index(this));
    }
});