JSFiddle - React, Tailwind, and code Playground
HTML
<input type="hidden" id="field" name="field" value="1">
<button id="change">Change</button>
JavaScript
alert($("#field").val());
$("#change").on("click", function(){
var newValue = parseInt($("#field").val()) + 1;
$("#field").val(newValue);
alert($("#field").val());
});