JSFiddle - React, Tailwind, and code Playground

HTML

<div id='node'>
    
    <input id="Form[0]_Phone" name="Form[0].Phone" type="text" value="">

    
</div>

JavaScript

newHtml = document.getElementById('node').innerHTML;
newHtml = newHtml.replace(/\d+/g, function (val) { return parseInt(val) + 1; });
alert(newHtml);