JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.0/themes/base/jquery-ui.css">
<form id="cancel" method="post" action="/">
    <input class="submitbtn" type="submit" value="Go">
</form>

<div id="dialog" title="Form submission">
    <p><span class="ui-icon ui-icon-alert" style="float:left; margin:0 7px 0 0;"></span>Are you sure?</p>
</div>

CSS

#dialog { display:none;}

JavaScript

$("#dialog").dialog({
    resizable: false,
    autoOpen: false,
    modal: true,
    buttons: {
        "Yes": function() {
            $('#cancel').unbind("submit.mine").submit();
            $(this).dialog("close");
        },
        "No": function() {
            $(this).dialog("close");
        }
    }
});

$('#cancel').bind("submit.mine", function(event) {
    event.preventDefault();
    targetform = this;
    $('#dialog').dialog('open');
});