JSFiddle - React, Tailwind, and code Playground

HTML

<form class="monitorForm">
    <div class="monitorAdd">textbox1
        <input type="text" tabindex="1">textbox2
        <input type="text" tabindex="3">
        <input type="button" tabindex="2" value="submit">
    </div>
</form>
<form class="monitorForm">
    <div class="monitorAdd">textbox1
        <input type="text" tabindex="1">textbox2
        <input type="text" tabindex="2">
        <input type="button" tabindex="3" value="submit">
    </div>
</form>
<form class="monitorForm">
    <div class="monitorAdd">textbox1
        <input type="text" tabindex="1">textbox2
        <input type="text" tabindex="2">
        <input type="button" tabindex="3" value="submit">
    </div>
</form>

JavaScript

var index = 1;

$("form input").each(function () {
    $(this).attr("tabindex", index);
});