JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://creativedream.net/plugins/jquery.modal/js/jquery.modal.min.js"></script>
<link rel="stylesheet" href="http://creativedream.net/plugins/jquery.modal/css/jquery.modal.css">
<form method="post" action="test.aspx" id="form1">
<div class="aspNetHidden">
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUJODIwMTY2MjU3ZGQVs14nJwqB/iIms8CsXW3SCzs22w==" />
</div>

<div class="aspNetHidden">

	<input type="hidden" name="__VIEWSTATEGENERATOR" id="__VIEWSTATEGENERATOR" value="75BBA7D6" />
</div>
    <div>
        <input name="myTextBox" type="text" id="myTextBox" onchange="checkalphabets(this)" />
        <input name="TextBox1" type="text" id="TextBox1" />
        

        
       
    </div>
    </form>

JavaScript

function checkalphabets(textbox) {
    var pattern = /^[a-zA-Z\s]+$/;
    if (!pattern.test(textbox.value)) {
        modal({
            type: 'warning',
            title: 'Warning',
            text: 'Only Alphabets allowed!',
            center: false,
             callback: function(){ $("#myTextBox").focus();}
        });
        
        exit;
        return false;
    }
    return true;

}
 $('.modal-btn').click(function() {

        $('#modal-window').hide();
     
    });