JSFiddle - React, Tailwind, and code Playground

HTML

<div id="error1" style="width:300px;background:#FF9999;border:1px solid #FF1919;height:18px;text-align:center;font-family:Verdana;font-size:10px;line-height:18px;display:none;">&nbsp;&nbsp;ERROR : Special Characters not allowed&nbsp;&nbsp;</div><br>
                                                <input type='text' name='customerName' style='width:400px;text-transform:uppercase' onkeypress="return IsAlphaNumeric(event);"/>

JavaScript

window.IsAlphaNumeric = function(e) {
    var result = /[0-9]/g.test(String.fromCharCode(e.charCode)); 
    document.getElementById("error1").style.display = result ? "none" : "inline";

    return result;
};