JSFiddle - React, Tailwind, and code Playground

by Rayon Dabre

HTML

<input type="text" name="myField['item_name'][]"> // index 0
<input type="text" name="myField['item_qty'][]"> // index 0

<input type="text" name="myField['item_name'][]"> // index 1
<input type="text" name="myField['item_qty'][]"> // index 1

<input type="text" name="myField['item_name'][]"> // index 2
<input type="text" name="myField['item_qty'][]"> // index 2

JavaScript

$('[name="myField[\'item_name\'][]"]').on('focus', function() {
  alert($('[name="myField[\'item_name\'][]"]').index(this))
});

$('[name="myField[\'item_qty\'][]"]').on('focus', function() {
  alert($('[name="myField[\'item_qty\'][]"]').index(this))
});