JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" name="folderName" id="folderName">
<input type="submit" value="click" id="sub">

JavaScript

$(document).ready(function () {
    $("#sub").click(function(){
var fn = $("#folderName").val();
    var regex = /^[0-9a-zA-Z\_]+$/
    alert(regex.test(fn));
});
});