JSFiddle - React, Tailwind, and code Playground
HTML
<input id="product_qty" type="text" name="product_qty" value="1" style="color: black">
JavaScript
$('#product_qty').click(function($(this).val($(this).val++);)
<input id="product_qty" type="text" name="product_qty" value="1" style="color: black">
$('#product_qty').click(function($(this).val($(this).val++);)